Most of the Harry Potter novels were self-contained. You could read them without having read any previous volumes in the series, since the author provided you with reminders of all significant events that had gone before. And when each volume ended, the major issues raised in that book had been resolved.

Always there was the continuing expectation of a final confrontation between Harry Potter and Lord Voldemort, of course, with other questions and puzzles along the way. But the reader felt, at the end of each book, that this, story, at least, had ended.

Not so with the sixth volume, Harry Potter and the Half-Blood Prince. A series that had been steadily darkening in tone -- growing up, in a way, along with its hero -- now darkened in another way: It seemed to some that we actually knew less about what was going on at the end of that book than we did at the beginning.

We were left dangling, with Harry in more peril than ever, Voldemort stronger than ever, the quest that had driven the story leading apparently to nothing, and Dumbledore dead.

(Though we must remember that dead things do live on in the world of Harry Potter. Rowling has been quoted as saying that Dumbledore is most definitely dead, and the fact that his face appears in a portrait in the Headmaster's office at Hogwarts seems proof enough that his death is genuine. Also, as Dumbledore himself said, "No spell can reawaken the dead" [Goblet 697].

(But "really dead" doesn't necessarily mean "gone." Isn't Fawkes the Phoenix fully dead before he rises from the ashes of his immolation? While it is unlikely that Dumbledore would fear death enough to choose to remain a ghost, it is possible that there is some deep magic involving the Phoenix that rises from the flames of Dumbledore's funeral pyre just before the location of the body is enclosed in a stone tomb: Could there be a good-magic equivalent of the dark-magic horcrux -- a survival of the soul on earth in a form that can return? Could it be that when Dumbledore says that as long as anyone at Hogwarts is loyal to him, he will not really be gone, he means it literally?

(The evidence for the possibility of Dumbledore rising like a Phoenix is not direct -- how could it be, without Rowling tipping her hand? -- but it is enough that if Dumbledore does show up again, alive, the readers will nod and say, "Yes, of course." In short, there is no particular reason to think that Dumbledore alone should be irrevocably, invisibly, and silently dead.)

But the biggest puzzle at the end of Prince is Professor Severus Snape. The head of Slytherin House at Hogwarts, Snape bears the sinister mark of Voldemort on his forearm and was one of the Death Eaters during Voldemort's previous bid for supremacy in the magical world.

We have learned that he functions as a double agent, pretending to be Voldemort's loyal servant, spying on Dumbledore, Hogwarts, and the Order of the Phoenix, while in fact he is really Dumbledore's agent, spying on Voldemort and the Death Eaters. Or is it the other way around? Is he only pretending to Dumbledore that he is only pretending to be loyal to Voldemort? The questions become, as they always do with double agents, quite circular and unanswerable until you see what the double agent does in the crisis.

Well, we have that answer, don't we? In the climactic scene, Snape kills Dumbledore, which appears to most as conclusive proof of his perfidy. And yet ... we also have reason to believe that what Snape did, Dumbledore wanted him to do -- that by killing Dumbledore, he was actually furthering Dumbledore's plan.

It was important to Dumbledore that it not be Draco Malfoy who slew him -- that Draco be protected from Voldemort, along with his whole malicious family. And Dumbledore was so determined to die (or was it just to keep Harry Potter safe?) that he put Harry under a spell of immobility -- and under his invisibility cloak -- during the crisis atop the tower. Dumbledore wanted no one to be in a position to prevent his death.

Yet what do we make of the critical moment?

"'Severus ...'

"The sound frightened Harry beyond anything he had experienced all evening. For the first time, Dumbledore was pleading" (Prince 595).

Pleading? One assumes -- Harry assumed -- that he was pleading for Snape to save him, or at least to refrain from killing him.

But he might just as easily have been pleading for him to do a thing that he knew Snape did not want to do: kill him before Draco could, so that Voldemort's plan to make a murderer of him would fail.

Snape approaches Dumbledore, pushing Draco "roughly" out of the way. Was that roughness to show his scorn for Draco's inability to commit murder? Or was it a bit of theatre, to make the others think that he scorned Draco when in fact he was making sure Draco was not in a position to change his mind and kill?

"Snape gazed for a moment at Dumbledore, and there was revulsion and hatred etched in the harsh lines of his face.

"'Severus ... please ...'

"Snape raised his wand and pointed it directly at Dumbledore.

"'Avada Kedavra!'" (Prince 595).

What did that look of revulsion and hatred mean?

Was it long pent-up resentment of and malice toward Dumbledore, which Snape was finally free to show as he murdered the man he had pretended to serve?

Harry's imperfect ability to interpret the meaning of Snape's facial expression? Harry had long since lost the ability to assign any positive meaning to any act, statement, or expression of Snape's. Was Harry simply wrong?

Was Snape's expression of hatred and revulsion merely theatre, a display for the benefit of the other Death Eaters beside him on the tower?

Or were his hatred and revulsion sincere enough, but caused by the violent act he was about to perform, the loathsome spell he was about to cast, the disloyalty that his loyalty was causing him to display?

Was it that revulsion -- at the idea of killing Dumbledore using a forbidden curse -- that caused Dumbledore to plead with him? Perhaps Dumbledore's "Severus ... please ..." was saying, in effect, I know you hate to do this, my friend, but please, overcome your revulsion and kill me in a way that will save Draco and win you Voldemort's utter trust.

Likewise, when Snape -- still sneering -- blocks Harry's attempts to use the unforgivable cruciatus curse, not just against himself but against another Death Eater, is he thwarting Harry as an enemy, or keeping the boy from turning himself into something evil by using such a terrible curse -- the way he shielded Draco in the tower?

After all, as Harry casts spell after spell at him, Snape does not fight back -- though Harry urges him to. Instead he blocks all of Harry's spells before he can cast them.

"Blocked again and again until you learn to keep your mouth shut and your mind closed, Potter!" Who was speaking here? The Snape who taunts Harry Potter -- the Snape who had just said "Coward, did you call me, Potter? Your father would never attack me unless it was four on one, what would you call him, I wonder?" (Prince 603)? Or the Snape who was a very demanding teacher, warning Harry which skills he would have to master before he could hope to be effective against Voldemort?

When the cruciatus is cast against Harry, he assumes it is Snape who did it -- but no, it is Snape who ends it and insists that the other Death Eaters respect Voldemort's order that "Potter belongs to the Dark Lord -- we are to leave him!" (Prince 603). But is he just obeying Voldemort? Or saving Harry Potter according to Dumbledore's plan?

In the aftermath, when Harry tells the remaining faculty what Snape did to Dumbledore, they all believe that Snape is therefore a murderer and a sincere Death Eater. But Rowling is careful to remind us, in McGonagall's words, "Snape. We all wondered ... but he [Dumbledore] trusted ... always ... Snape ... I can't believe it...."

Are we to believe what they all believe, that Snape is guilty? Or are we to heed McGonagall's unwitting advice, "I can't believe it"?

As if to make sure we got the point, Rowling has Tonks say, "But Dumbledore swore he was on our side! I always thought Dumbledore must know something about Snape that we didn't..." (Prince 615)

Of course, immediately after this, Harry Potter offers what he thinks was Dumbledore's "ironclad reason" for trusting Snape -- a reason that doesn't seem so ironclad in retrospect. "Dumbledore believed Snape was sorry James [Harry's father] was dead? Snape hated James..." (Prince 616)

And thus Rowling tosses us back and forth. We know whom to like; we even know, mostly, who is honest and means what they say. What we don't know is who is right.

If one thing has been clear throughout the series, it is that Dumbledore trusts Snape; could he have been wrong? And even if Dumbledore was right to trust Snape's loyalty so far, can Snape be trusted to continue to serve Dumbledore even after Dumbledore is dead?

The Author and the Character

In one sense, the definitive answer can only be found by reading the final volume in the series.

After all, these books have an author, and the author is free to have her characters do whatever she wants them to do. Until Rowling's words on paper turn into scenes in our minds as we read them, the answer to that question might still turn out either way -- or some twisted combination of tortured moral reasoning and contradictory actions on Snape's part that keeps us guessing right to, or even past, the end.

Or is she really free to do just anything?

There is a logic to how a literary character is formed, especially be a writer of such visceral power as Rowling has turned out to be.

I think the power of the Harry Potter books surprised even Rowling. Certainly there is a progression of tone from the first volumes through the later ones. I spoke before of darkening, but it might rather be viewed as a de-lightening. The first volume was like J.R.R. Tolkien's The Hobbit in that it was self-consciously a children's book, full of delightful jokes. Dumbledore, like the Wizard Gandalf in The Hobbit, was a trickster, a jester. The world was full of wonders that were, quite simply, fun; game-playing and riddle-solving were at the heart of the story. It was a romp. Even including the climax, the book was light -- in physical weight, in voice, in mood, and in moral consequence.

But the later volumes steadily progressed to ever-more-serious consequences, with ever-fewer moments of genuine frivolity. There was still humor, but it had a darker edge.

Why?

Because Rowling was no longer telling a children's story, she was telling a story that happened to be about children. The light tale-for-children tone turned to the much darker hues of a story rising out of the author's unconscious.

Much has been said about how Rowling had the whole series planned from the beginning. I believe that this is true -- up to a point. The asymmetry in the lengths of the books suggests that Rowling began to fill her pages, not with deliberate (and intellectual) inventions, but with story that simply flowed and often went in directions that simply felt right to her.

Most important, she went from the sharp, clear black-and-white morality of the first book to a far more shaded and nuanced view of good versus evil. You could almost always tell good guys from bad guys in Stone because good guys were nice to Harry and bad guys were mean.

But by the time we found our way through Prisoner of Azkaban, we had a "good guy" -- Sirius Black -- who had been, as a student, perfectly capable of setting up the probable murder of his fellow student Severus Snape. Yet Black remained on the good-guy team.

Harry himself becomes morally ambiguous. His "pranks" and sneaking and spying may always have, in his mind, good motives, but they don't always have good consequences, and while he is not motivated by pure malice, he does delight in the occasional malicious prank.

More to the point, on many of the occasions where Snape accuses Harry of having done something dire, Harry is in fact guilty of rule-breaking or worse. Harry cooperates in crimes, like hiding and helping smuggle Hagrid's illegal dragon, and he almost never calls on even the most trusted authorities to help him. We see his deeds, correctly, as heroic -- but they could also, without much twisting, be made to prove that, as Snape accuses, Harry Potter believes that he is above the law -- that he is free to pick and choose which rules to obey, depending on what seems good to him at the moment, based only on the information he has.

We might be glad that Harry cheats in order to prevail in the Tri-Wizard Tournament in Goblet -- and it would take a moral cretin not to see that Harry's noble behavior in putting the lives of others ahead of his own chance of victory certainly earns him absolution for his rule-bending. But the fact remains: Harry Potter's larger motives might be good, but he is dangerous: He never has complete information, and yet frequently puts his own moral judgment ahead of public laws and wiser people's advice.

This is not uncommon in fiction -- how many hard-boiled detectives are barely distinguishable from the criminals they pursue? The difference between a knight and a thug is often merely the color of his armor.

What makes Harry's moral ambiguity interesting is that Rowling points it out. He is the hero; but he does not always do the right thing, either in the moral or the practical sense. And characters like Snape and Draco Malfoy may be cruel and malicious, but they do not always do the wrong thing.

The result is that the moral universe of the Harry Potter novels moves from clarity to a deepening chiaroscuro in which truth can lurk in shadows and error can stand in the sun. This is the kind of thing that authors rarely plan; it happens when they themselves become immersed in the tales and let their unconscious mind lead them down paths they had not anticipated.

So ... what is Snape?

A character that has been planned from the beginning to act in certain ways, so that we can see the careful hand of the author preparing him for his role in the final scenes of the final book?

Or is he a character who served a useful function in the earlier books, was almost abandoned when other characters served that function better, but then reemerged from the author's unconscious into a powerful role that expresses her deep inner conviction that it is nearly impossible to judge ultimate moral worth solely from outward behavior?

There are two logics working here:

1. The character is the servant of the story. The author has certain jobs that need to be done in a tale, and devises characters to carry out those jobs. The characters, then, follow an artistic logic.

2. The author is also the servant of her own most deeply held beliefs -- the things that she believes without even knowing that she believes them. Characters that endure in a well-made work of fiction are invariably captured by the author's unconscious and are bent in ways that the author might not have predicted. Thus the logic that drives the character -- the system of cause-and-effect demonstrated in the character's choices -- is governed, not entirely by a conscious, artistic plan, but also by the author's inner imperative to create a fictional world that demonstrates the secret moral and causal universe in which she lives.

In other words, the first logic shows us the author's conscious choices -- what the author believes that she believes. The second logic is where the genius rather than mere cleverness comes into play: It shows us what the author believes without knowing that it is possible to believe anything else.

Look at how the pivotal character of Gollum grew in Tolkien's classic tales of Middle-earth. In The Hobbit, Gollum exists for one purpose: To give Bilbo the Ring. But he is an intriguing character; for reasons Tolkien himself doesn't understand, he matters. In fact, he functions as an anti-hobbit, a creature much like Bilbo but the moral opposite.

When Tolkien set his hand to writing the sequel to The Hobbit, at first he only knew that he wanted to have hobbits meet Tom Bombadil, and so he put together a traveling party and sent them into the Old Forest where they met the characters about whom Tolkien had been writing poems for many years. And then ... nothing. He had nowhere for them to go, nothing for them to do. And as many readers have felt, what he'd already had them do was nearly nothing -- it was hard to care much. The events were just one thing after another.

This version of the opening of Fellowship of the Ring was the draft that followed artistic logic alone. And, as almost always happens, the draft was empty. Artistic logic does not create great stories, only outlines of stories.

Then, as Tolkien famously explained, he got to the inn at Bree and met a character named Strider. Strider intrigued him -- an unconscious, visceral response -- and in figuring out who Strider was and what he was doing, Tolkien found the real story of Lord of the Rings.

Still, he left that story-empty section intact, making only one significant change in the story flow. He had Gandalf tell Frodo the story of the original finding of the Ring by Deagol and Smeagol -- and told of how Smeagol became Gollum.

In other words, the only change in that opening sequence that was required to make the novel satisfy that inner, unconscious logic, was to move Gollum to the center of the tale. He was not the hero; nor was he the monster. Instead, he was the center of moral ambiguity, the character who, seeming evil, might also serve the good. Other, lesser characters might also show moral ambiguity (one thinks of Saruman, Theoden, and Denethor), but none is as central to the story as Gollum.

Snape, I believe, is the Gollum of the Harry Potter books. Born at first to be little more than a convenient obstacle and a red herring, he graduates to become the center of moral ambiguity. We cannot know (as we could not with Gollum) which way he will turn. We have seen his malice, but much of it has been justified -- he was more victim than victimizer in his school days, and it was "good guys" who oppressed him. So as we prepare for the final volume in the series, we can see that everything comes down to this: What choice will Snape make?

I do not anticipate that Rowling will push Snape through all of Gollum's paces: Gollum ended up choosing evil, and only inadvertently served the cause of good. There is no reason to think that Rowling's inner logic will echo Tolkien's -- indeed, that is highly unlikely. It is only those who are using artistic logic -- those writers who have consciously imitated Tolkien -- who merely echo his deep choices. Rowling may have learned eclectically from all her literary sources, but she is enthralled by none of them. The Harry Potter books have grown from a conscious plan into an unconscious unfolding of a deeply believed inner universe -- they have become true art rather than mere planned art -- and so Snape, while fulfilling Gollum's literary function, will act out the script that feels right to Rowling.

That very fact is actually our key to seeing where Snape's character is going: As we track his progress through the books and see how Rowling uses him, we can discover what he means to her as well as what he does for the storyline. We may not be able to come up with a definitive answer -- after all, Rowling's unconscious logic may contain twists as yet unrevealed to us -- but we can still come to conclusions that have the ring of truth to them.

I am not proposing that we psychoanalyze Rowling. Fiction is a poor tool for that. Rather I am proposing that we track Snape's progress through the books to see where she has consciously pointed him, book by book, and where it seems she found herself unconsciously pointing him. It is only when he becomes a deeply important character to Rowling that he also becomes deeply important to us.

Snape's Progress

Rowling is on record as saying that she planned all seven volumes from the beginning. But just how detailed was that plan? Did she, in writing volume one, know exactly what she would do with all the characters who were still around in volume seven? I sincerely doubt it, if only because the tone of the series has changed so dramatically -- darkening, deepening, and lengthening from volume to volume. Rowling is not now the same writer she was at the beginning, and however detailed her outline was, she would have been hampered, if not shackled, by having to stick to an outline she devised when she was still a relative novice.

It is even possible that her "outline" for the final volume was, in its entirety, "Harry has it out with Voldemort."

And even if she had far more details sketched out for the final volume, I'm willing to bet that as she really got to know the characters by writing about them, she changed her ideas about the roles many of them would play later in the series. It will be interesting, when scholars at last have access not only to the books but also to her working notes at every stage, to see how the creativity that emerges in the writing process transformed her plans for the series.

I have read novels where the author went through the normal process of discovering interesting, unplanned things about his characters -- and then reined them in or cut them off so he could fulfil the original outline. Rowling shows no signs of having done such violence to the ideas that come up in the process of writing; on the contrary, each volume has been more willing to "learn" from the books before, which almost certainly means that there are many things in the later books that were not in the original outlines -- and, quite possibly, things originally planned that will no longer happen, or will mean radically different things when they occur.

So in tracking the way Rowling uses and develops Snape through the six volumes we have at present, I believe we will see a character become far more important to the whole series than he was originally intended to be.

And even if his exact role in the overall series was plotted from the start, it is certainly true that he is used very differently from book to book.

Stone. In the first volume, Snape's primary role is as decoy. We don't meet him until more than a third of the way through the book -- but that's only because Harry doesn't get to Hogwarts till then. Everything beforehand serves the function of bringing Harry -- and therefore the readers -- from the real, modern world into the wizarding world. Throughout those pages, it is almost all comedy, and even when we get to Hogwarts, we have silliness like Dumbledore saying "a few words ...: Nitwit! Blubber! Oddment! Tweak!"

Indeed, silliness seems to prevail; if Dumbledore had remained the clownish fellow who had everyone sing the school song to whatever melody they chose, it is doubtful many readers would care as much about the series as we do.

In the midst of the silliness, though, Dumbledore does give the warning that signals the beginning of the real story: he warns the students not to go near the "third-floor corridor on the right-hand side" unless they "wish to die a very painful death" (Stone 127).

The very next chapter is entitled "The Potions Master" -- like the sixth volume of the series, it is named for Snape. But this is not the Snape of Harry Potter and the Half-Blood Prince. He is harsh, he is unfair, he singles Harry out for negative attention, and he ignores Hermione's competence. (He also takes only a single point from Gryffindor for Harry's "cheek" -- in later volumes, point inflation sets in and similar offenses result in ten, then fifty points being deducted).

Snape's nastiness was necessary to further the plot of this volume: There had to be a red herring, someone Harry and his friends could believe in as the likely villain so that the real perpetrator of evil deeds is not suspected.

Thus Snape gets a lot of pages in the second half of the book. When the real villain is revealed, however, we learn that far from Snape being the villain, he was in fact acting to protect the school and, on occasion, to save Harry Potter himself.

Why does he do this? Because Harry's father once saved his life. As Dumbledore explains -- "dreamily," for Rowling is not yet taking Dumbledore seriously -- "I do believe he worked so hard to protect you this year because he felt that would make him and your father even. Then he could go back to hating your father's memory in peace" (Stone 300).

To me, this is all the evidence I need that Rowling did not know the details of Snape's relationship with James Potter when she wrote the first volume. While it is quite believable that Dumbledore would not choose to tell Harry that Snape also felt guilty for having inadvertently provoked Voldemort into killing Harry's parents, it is not believable that Dumbledore, knowing the whole story, would "dreamily" say "Then he could go back to hating your father's memory in peace." It is too light, trivial, and dismissive a thing for Dumbledore to say about Snape, if he (and Rowling) had then known Snape's role as a trusted confederate and former Death Eater responsible for Voldemort hearing of the prophecy that provoked his murder of Harry's parents.

Chamber. In the second volume, Rowling still is not taking her own fictional world entirely seriously. In the Hogwarts of the later books, it would simply not be believable that Lockhart would be hired in the first place, or that he would remain in his position for more than a few days. Rowling clearly recognized some of these believability problems from the earlier books, when later on she goes to some lengths to give us Dumbledore's justification for keeping Trelawney on the faculty.

Even though Chamber gets Harry to Hogwarts far more quickly than the first, there are far fewer references to Snape. That's because his role in the novel is to direct suspicion toward Harry Potter, and to serve as comic relief when he is enlisted by Gilderoy Lockhart in the dueling demonstration.

Snape's last appearance in the book is more than seventy pages before the end, when Draco suggests that Snape ought to be made Headmaster to replace the suspended Dumbledore. Snape's reaction to this is to reassure Draco that Dumbledore will probably be back soon enough, "though he couldn't suppress a thin-lipped smile," and he "smirked as he swept off" (Chamber 267).

This is not the Snape who can hide his thoughts and feelings from Voldemort -- rather this is the Snape that is still nothing more than a device to annoy and harass Harry and his friends. This version of Snape covets not just the Dark Arts position, but the Headmaster's office as well. There is no trace of this sort of trivializing of Snape in the last few volumes.

Before that, we saw Snape when Harry and Ron sneak past him under the Invisibility Cloak -- and Snape conveniently sneezes so he doesn't hear their passage (Chamber 259). And before this trivial use of Snape, the last use of him was in the duel where Harry's ability to speak to snakes was revealed (Chamber 193).

It is clear in Chamber that Snape is definitely a minor character, only slightly more important than most other professors, and far less important than Hagrid. There is no promise here of what he's going to become. He is merely a caricature left over from the first volume, ready to be trotted out when he is needed ... to sneeze.

Azkaban. In Azkaban, the series takes its first serious turn toward the depth of the later volumes. Sirius Black plays the part that Snape played in the first volume -- he's the red herring that seems to be a villain and then turns out to be trying to help Harry. But this time the story centers around Harry discovering far more about his father, and the most important character is actually Lupin, who guides Harry through his discovery that he has the same Patronus as his father, and that James Potter was part of a group of four very talented magical pranksters whose games sometimes got out of hand.

When Ron's pathetic rat Scabbers turns out to be the animagus who actually committed the crimes Sirius Black was convicted of, we see the best example of Rowling taking something very minor from an earlier book and investing it with far more importance. Scabbers is barely present in Chamber, but as soon as Rowling knows that he matters after all, he's brought back in full force. When Rowling decides a character is going to be important at the climax, she moves him to the forefront -- which, with Scabbers, consists of his ongoing struggle with Hermione's cat. What seems like a running gag actually serves to keep us aware of a character who is going to be revealed as a villain in the great "reveal" scene.

Snape is important in this plot, but primarily as a complicating factor. He hates Lupin but still prepares the potion that keeps him from turning wolf at the full moon; yet he gives very strong hints to the students about what Lupin really is, and it is Snape who provides the last-minute jeopardy, turning Sirius Black over to the authorities and lobbying for his immediate execution.

As with the first volume, Snape's role is important in the immediate plot, but not yet in the long-range story. It's as if Rowling came up with the idea that Snape's life was once saved by James Potter solely to make it believable, in Stone, that someone as malicious as Snape would have been trying to protect Harry after all. Perhaps Rowling thought more about how such a thing could come to be and came up with the details of the foursome who created the Marauders' Map and how James Potter saved him -- from a prank that was heading for something really ugly.

Snape remains in this volume as vindictive as ever, but at least now his malice seems more justified. We also begin to see more clearly that he is becoming an ironic figure: As in Chamber, he constantly catches Harry in the middle of some kind of mischief, but whereas in Chamber he invariably assigned the worst possible motive to Harry's actions, even when his version was absurdly, obviously wrong, in Azkaban, Snape's accusations against Harry are often very accurate. Harry really is violating rules, and not trivial ones; Harry really is constantly lying; Harry really is so arrogant that he thinks that he knows better than anyone, and withholds the truth about what he's doing even from Dumbledore.

Thus Snape is moving closer to the center of Rowling's attention. She is using him now, not just as an obstacle (though he still is one), but also as a tool for pointing out Harry's own moral ambiguity. Harry leaps to conclusions; Harry deceives some of the very people he ought to trust most; Harry has contempt for rules even when they exist to protect him and others. Snape's fury at Harry may have begun with the malice that James Potter earned, but it is Harry's own fault that Snape is able to find so very much ammunition to use against him. Rowling is intertwining Snape and Harry in a far more complicated way than before.

Goblet. When this fourth volume opens with what amounts to a summary of the story-to-date (which Rowling no longer attempts in the later books), it is significant, I think, that Snape does not even rate a mention. Nothing he has done in the previous books is actually important to understanding what is now happening. But this is the last time that is true.

For even though Snape barely appears in this book, in the scene in the cemetery, where the Death Eaters assemble to watch Voldemort resume his physical body and, they assume, kill Harry Potter, we get our first glimmer of Snape's role as double agent: Voldemort's trusted servant, reporting to him about Hogwarts, and Dumbledore's spy, reporting to him about Voldemort and the Death Eaters. Not that Snape is present -- he is only referred to obliquely; and the most obvious reference, that seems to refer to him, in fact refers to Barty Crouch, who is masquerading as Mad-Eye Moody. (So once again Snape is a red herring, distracting Harry from the real enemy.)

The real statement of Snape's new role comes when, near the very end of the book, Dumbledore asks Harry and Snape to shake hands as loyal compatriots in the struggle against Voldemort, and then turns to Snape and says, "You know what I must ask you to do. If you are ready ... if you are prepared ..." (Goblet 713). Snape turns pale and says "I am"; then he leaves to join Voldemort and pretend to be his loyal servant.

Among Snape's few appearances earlier in the book is what is arguably his cruelest moment, when he humiliates Hermione about something she can't help, her personal appearance (Goblet 300).

It is also in this book that Snape gives his clearest list of complaints to Harry, right to his face: "To me, Potter, you are nothing but a nasty little boy who considers the rules to be beneath him" (Goblet 516). Snape accuses Harry of lying, whereupon Harry lies to him repeatedly. Snape is not unjustified when he threatens Harry with veritaserum -- and both Harry and the readers understand that if Harry were forced to tell the truth to Snape, the truth would not vindicate Harry the way it would have in Chamber.

For the first time in the series, the reader can't help but recognize that Snape has a point. For the first time, Harry's shenanigans are seriously questioned -- and Snape does the questioning. This is how Rowling prepares us to see Snape as being something other than malicious, and we are not appalled or incredulous when Dumbledore trusts Snape with his mission among the Death Eaters.

Phoenix. Snape's new role in the story -- as the member of the Order of the Phoenix who is fulfilling the most dangerous assignment of all (at the moment, at least) actually keeps him out of the book for a long time. He shows up briefly in page 69, where the kids talk about how much they loathe him, and then surfaces again only as potions teacher at Hogwarts, where he evanesces a potion that Harry did, in fact, botch (232-234). It's annoying, but not as vicious as things Snape has done in the past. He shows up again on page 309, again merely as a teacher.

Why is he so invisible? Because Dolores Umbridge is filling the role of persecutor now, providing a powerful contrast with the relatively mild punishments Snape inflicts. The contrast is, I think, deliberate: Rowling is rehabilitating Snape a little, making him seem better than before because Umbridge is so much worse -- and for so little reason. Snape, at least, had some justification for resenting Harry; Umbridge is simply evil.

When, on page 362, we begin Umbridge's visit to Snape's class, we see Snape acting with dignity. Gone are the smirks that afflicted him constantly in the early books. Now his answers are quiet, his expression unfathomable; when his lip curls, it is with impatience at genuine stupidity. He still wipes out Harry's potion yet again and assigns him an extra essay, but now we see him as a man with some self-control, and his punishments as a mere annoyance compared to Umbridge's sadism.

On page 400 we catch a glimpse of Snape overbooking the Quidditch field for Slytherin's team, and then don't see him again until he comes to Harry with the news that Snape is going to teach him occlumency, at Dumbledore's request.

Then begins a rather intense series of scenes between Harry and Snape, as Harry resists Snape's lessons and Dumbledore's orders (typical of Harry) and does not practice occlumency, preferring to keep having his dreams of the room where a great and important secret is being kept. When we finally discover what was really going on with these dreams, we realize that Harry was being suckered by Voldemort, and if he had paid more attention to Snape, things might have turned out better.

Meanwhile, though, we learn considerably more about Snape's character -- including Harry's indecent penetration of Snape's secret memories (Phoenix 639-650). The result of this act is that Snape discontinues the lessons in occlumency, Harry is appalled at his father's cruelty and rushes to Sirius Black to help with his disillusionment -- and the readers now have vastly more sympathy with Snape than ever before.

This is where Snape turns: Rowling has elevated him to become a complex character rather than the iconic figure he had been before. We actually care about him as a person, and not just because of what he might do to interfere with Harry's plans. Snape is the hero of his own story now, and we are interested in seeing what becomes of him for his own sake. It is only now that Snape becomes worthy, as a fictional character, of playing the role that is being prepared for him in the final volume.

On page 833, Harry's and Dumbledore's assessment of Snape is patently unfair. After telling Dumbledore that "Snape stopped giving me Occlumency lessons! ... He threw me out of his office!" he goes on:

"'Snape made it worse, my scar always hurt worse after lessons with him --' Harry remembered Ron's thoughts on the subject and plunged on. 'How do you know he wasn't trying to soften me up for Voldemort, make it easier for him to get inside my --'

"'I trust Severus Snape,' said Dumbledore simply. 'But I forgot -- another old man's mistake -- that some wounds run too deep for the healing. I thought Professor Snape could overcome his feelings about your father -- I was wrong.'"

Harry is grossly unfair -- he neglects to point out that Snape threw him out of his office after Harry indecently pried into a hidden memory that Snape clearly did not want him to see. And Harry also neglects to point out that even when Snape was teaching him, Harry didn't really try to learn how to blank his mind.

Dumbledore is unfair to answer Harry's wild accusations with the mere assertion that he trusts Snape, followed by an irrelevant statement that seems to throw the blame for the failure of the lessons on Snape alone, because he couldn't "overcome his feelings about" James Potter.

I don't know how many readers reacted to this passage as I did -- perhaps most took these statements at face value. But I found myself mentally defending Snape exactly as, in previous book, I mentally defended Harry against Snape's wild accusations. For me, at least, Rowling had succeeded in momentarily transferring my allegiance to Snape.

Prince. Volume six is Snape's book, to put it simply. He is the title character. The volume begins and ends with his actions. Throughout the story, Harry has a close relationship with Snape's younger self through his marginal notes in a potions book. Thus we learn to experience Snape as a brilliant, creative young wizard -- though we don't know it's Snape, of course, until after he has killed Dumbledore.

Ay, there's the rub -- Snape does kill Harry's sole remaining father figure.

Hermione repeatedly points out to Harry that whatever he learns from the Half-Blood Prince's book, he could have learned just by paying better attention to Snape's lessons right from the start. It become perfectly clear to us that if Harry had not been distracted from Snape's teaching by his loathing for the man, he would have become a better wizard.

At the same time, it was hardly Harry's fault that Snape goaded him mercilessly before Harry had even had time to do anything wrong. But just as Snape never got over his treatment at the hands of James Potter and friends, so Harry couldn't get past Snape's malice in order to learn from him. Snape's loathing for James Potter didn't stop Snape from becoming a powerful wizard with skills that, in one area at least, Occlumency, surpassed those of Voldemort. But Harry's loathing of Snape did stop him from learning the very things that Snape was uniquely capable of teaching him.

This volume draws Snape upward to the level of Dumbledore in importance to the story. Meanwhile Ron and Hermione become less central -- they are shut out of the core story of this volume, serving more as distractions and comic relief. It's as if Rowling has to keep reminding herself to include them, because the energy of the story is now being generated by Harry, Dumbledore, Snape, Draco, and Voldemort himself. Harry's enemies are, in fact, more important to this story than his friends.

But that's partly because this is the first volume whose story doesn't actually end. None of the major problems in this book are resolved -- only the relatively trivial problem of the identity of the Half-Blood Prince. Instead of being self-contained, this volume is rather a long first act, setting up the final volume of the series. There are no important new characters introduced; rather, the existing cast is thrust forward into new, more demanding, more mature roles.

And when that happened, Snape came into his own. From the red herring role in the first volume to the complicator, obstacle, and even comic relief he was in the next few, Snape has forced his way into being one of the most complex and interesting characters in the series. He matters now.

Which is why we can be sure that Rowling has no intention of throwing him away. If he is now merely another Death Eater, serving Voldemort faithfully, all that preparation was essentially wasted. We've seen what happened to Wormtail after his prominent role at the climax of Azkaban -- once he joined Voldemort, he showed up now and then, but we didn't actually care about him. Rowling wasted no effort trying to make him into somebody.

Thus Rowling's elevation of Snape into major-character status only makes artistic sense if Snape's actions in the next book are pivotal. And his actions will only be pivotal if they are in doubt. And they will only be in doubt if we are given clear reasons to believe that his killing of Dumbledore might not have been the evil action that Harry and his friends assume it to have been.

Speculations on Character

Another approach to predicting how Snape will act in the final book is to try to understand the traits that dominate his character.

Snape As Slytherin. Slytherins are not necessarily evil -- what typifies them is ambition.

Persons of limited ability can only satisfy their ambition by attaching themselves to someone stronger who will raise them up. Thus ambition leads to slavish loyalty -- but to immediate abandonment when the person they have attached to seems to be slipping or failing.

We saw plenty of that during Voldemort's time as one-seventh of a soul, after he "died" from the rebound of his killing curse on baby Harry. A few remained loyal, clinging to their faith in Voldemort's supremacy; others denied him immediately, lest they be brought down by his fall.

Slytherins, however, make untrustworthy servants and untrustworthy masters. Because they are ambitious, they will resent the one they serve -- Voldemort's followers, except perhaps a few demented ones like Bellatrix -- do not love him; on the contrary, they hate him, because they resent him for overshadowing them. Each wants to be supreme; it is only because Voldemort exists that their ambition is suppressed.

And Voldemort will also resent everyone who helps him. He wants to stand alone. Once he stands without significant enemies or rivals, he will certainly destroy everyone whose help he depended on to reach that position, because it will be unbearable to him to be in anyone's debt.

Now let's consider Snape as an exemplar of the Slytherin personality. Quite independently of any connection with Voldemort -- before he was a Death Eater, in other words -- Snape's ambition led him to style himself, albeit privately, as "The Half-blood Prince." He was brilliant and knew he was brilliant; he created new spells and invented new potions. He learned occlumency to the degree that he could hide his thoughts from anyone.

No wonder his humiliation during school days at the hands of Sirius Black and James Potter could not be forgotten, and colored his response to James's son -- especially since one of the unhappiest memories was an occasion when James afflicted him with a spell that Severus Snape himself had invented.

Snape's ambition is more telling when it comes to his relationship with Voldemort. The second-most-ambitious wizard in the world will not be Voldemort's servant, but his rival. No one will suffer more frustration at Voldemort's supremacy than the person who believes that position is his by right. In fact, it is no accident that Snape's background echoes Volemort's in being the child of a miserable mating between a cruel Muggle and a lovestruck wizard woman. Both of them loathe "Mudbloods" precisely because they are themselves tainted.

But they are definitely not the same person. Voldemort, in his youthful days as Tom Riddle, had the self-control to make himself seem a model student at Hogwarts -- he became head boy even as he was already committing murders and creating horcruxes. He was attractive and gathered followers around him.

Snape, on the other hand, was vain enough not to bother altering his appearance in order to seem attractive to others. This might mark him as less ambitious than Voldemort; or it might mark him as being more proud, at least in his youth, for he would not stoop to seek the approval of anyone he did not respect. Perhaps he is less ambitious than Voldemort -- or more proud.

What is certain is that if there is anyone among the Slytherins of the wizarding world who would hate, resent, and happily work against Voldemort, it is Snape. If he serves Voldemort, it will be with resentment at having to be subservient; but that is also true if he serves Dumbledore.

Knowing that Voldemort is immortal must be exceptionally galling to an ambitious wizard -- Snape knows he will spend his whole life subservient to Voldemort, even if Voldemort doesn't eliminate him. His ambition will never, never be satisfied.

So if Slytherin ambition really is the primary key to Snape's character, then he himself has no loyalty to anyone. He hides his feelings from all, and pretends loyalty to both Dumbledore and Voldemort, biding his time. However much Snape hates Harry Potter, he will not allow permanent harm to come to the only person who might have the power to defeat Voldemort.

In this light, it makes perfect sense that Snape sees Harry as weak, careless, vain, grandiose, and not particularly talented. Because of the magics of other people that protect Harry, the boy wizard has so far bested, or at least evaded, Voldemort at every encounter. Snape may well believe that if he manages to be present at the deadly final encounter between Harry and Voldemort, then he might be able to turn circumstances toward satisfying his own ambition:

1. If Harry wins, Snape would believe he could certainly kill Harry, having no magical bond with him the way Voldemort has. No linking of wands, no connection of minds through the scar -- Snape can simply finish him off and stand alone in Voldemort's place.

2. If Voldemort wins, but is seriously weakened by the encounter, Snape could strike instantly and fatally, killing Voldemort himself.

3. If Voldemort wins, and is all the stronger for it, then Snape can continue to present himself as Voldemort's loyal servant, and at least survive until he can find some other way to best Voldemort -- or until Voldemort eliminates him precisely because he owes him so much.

This view of Snape is not inconsistent with anything Rowling has shown us of the man. This might be precisely how she is planning to use him at the climax of the seventh book.

In that case, we must view Snape as having been a triple agent, deceiving both Dumbledore and Voldemort.

But Rowling will then have the obligation of explaining to us why Dumbledore trusted him so completely.

Snape As Love-Starved Genius. Let's leave in place our assumptions about Snape's ambitions, but now let's say that a hunger for love and/or respect is another determining factor in his character.

When Harry cast his protego spell against Snape during an attempt to teach him occlumency, and was given a rush of Snape's memories, what did he see?

"A hook-nosed man was shouting at a cowering woman, while a small dark-haired boy cried in a corner ... A greasy-haired teenager sat alone in a dark bedroom, pointing his wand at the ceiling, shooting down flies ... A girl was laughing as a scrawny boy tried to mount a bucking broomstick ..." (Phoenix 591-592)

It is tempting to read into this a profound loneliness -- the pride in Snape hates humiliation, but is humiliation perhaps worse in front of women? Or is he merely starved for respect?

Or is it parental love that he needs? Is that what he gets from Dumbledore? What he loves about Dumbledore is not that he is good, but that he shows respect and trust to Snape?

Far from being love-starved, however, Snape seems to seek to be alone. When he has the respect and devotion of Draco and his fellow students, Snape definitely favors them -- but he is quite capable of being stern with them when he feels like it, and there is scant sign of him sharing intimate friendship with anyone. If he wanted love and respect, he could have dressed to conform while he was a student and offered an occasional smile or sign of warmth; it seems more likely that that particular part of him has been shut down.

Snape Surly Good Guy. Maybe Snape secretly loves the Good and loathes Evil. Perhaps this will lead him to save or help Harry Potter, or destroy Voldemort, at the end. Perhaps this is why he has served Dumbledore all along -- including, finally, killing him when that formed part of Dumbledore's plan.

By that view, one could see all of Snape's meanness as an act. But it's an act he maintains so consistently, relentlessly, and egregiously that one has to think it's an act that he enjoys -- which would mean it wasn't an act at all.

Snape is so consistently, needlessly cruel and unfair that he is obviously ruled by malice. There are plenty of examples in his treatment of Harry, but the example that sticks out most to me is his response when a stray curse has left Hermione with overgrown front teeth. "I see no difference," says Snape, sending her away in tears. To needlessly hurt a socially powerless child, however annoying she might be, is a cruelty that is hard to explain away.

So maybe he is a good person who is also mean. Doesn't that also describe the way we are expected to view James Potter and Sirius Black? Black was a "good guy" even though he once, as a cruel joke, sent Severus Snape Snape down a tunnel leading to a ravening werewolf -- an act of attempted voluntary manslaughter at best.

James Potter knew this was going too far and stopped Snape just in time, saving him -- but it was also James Potter who maliciously, for nothing more than his own and Sirius's amusement, dangled Snape upside down, exposing his dirty underwear and skinny body in front of several girls.

If people can behave this way and still be "good guys" in these books (though to my mind, Sirius Black stopped being a good guy as soon as I knew these things about him), then one can only admit that Snape might be a good guy, too.

One can more easily justify Snape's meanness than that of James Potter and Sirius black. Snape is ashamed of his own ancestry and therefore especially despises "Mudbloods," and Hermione can be an annoying know-it-all. As a know-it-all himself you'd think Snape might be a bit kinder; but it's just as logical that what he hates in Hermione is precisely her resemblance to himself; since she is an unattractive (at that point in the series) know-it-all, and so was he, he hates her as he hates those aspects in himself.

Or perhaps he hates her because, despite her brains and mudblood ancestry and unattractiveness, she has found some very close friends. Perhaps his malicious treatment of her has to do with the fact that she was accepted by Harry Potter and became part of his group, while Severus Snape was never accepted by Harry's father, or admitted into his group.

As to Snape's malice toward Harry, one can find some justification in Harry's resemblance to his father, his contempt for the rules, and the awe that others hold him in. To Snape, this was simply James Potter all over again -- and except for not being anything like the outstanding student his father was, Harry seems to go out of his way to justify Snape's opinion of him.

So, from what we see of Snape's pointlessly malicious actions, he is somewhat more justified than James Potter and Sirius Black ever were in their treatment of him. If we admit them as "good guys," then we certainly cannot rule Sirius out, at least not on that basis alone. (It was fine that Sirius and Lupin both repented their bad acts toward Snape, having learned to be better people. But their cruelty to him arose out of their nature, and not out of any harm Snape had done them, while Snape has genuine grievances against them, and damage done to him in adolescence does not evaporate just because the perpetrators later regretted what they did. To say he should have gotten over it is to hold him to a higher standard than most people are able to achieve.)

We have seen Snape's malice and vindictiveness, but what we never see from him is actual evil. When Snape punishes Harry, it is usually for genuine offenses, and if the punishment seems excessive, it is never actually cruel. In case we miss the point, Dolores Umbridge's vicious physical punishment of Harry during detention shows us what a truly evil person might do with a position of absolute power over an annoying child.

The line between meanness and evil seems to be clearly drawn in the moral universe of the Harry Potter series. As Bellatrix says to Harry when he casts the Cruciatus spell on her in the Ministry of Magic: "'Never used an Unforgivable Curse before, have you, boy?' she yelled.... 'You need to mean them, Potter! You need to really want to cause pain -- to enjoy it -- righteous anger won't hurt me for long -- I'll show you how it is done, shall I? I'll give you a lesson --'" (Phoenix 810).

We know Bellatrix is evil -- she drove Neville's parents insane with the cruciatus and took pleasure from it. And that is the dividing line, where ambition and pride cross over into true evil -- that the death and suffering of others become ends in themselves rather than merely means to an end. This is what marked Voldemort from the start, even before he came to Hogwarts as Tom Riddle. He was a torturer simply for the pleasure of it; when he killed, he took trophies, because it was an occasion he wanted to remember.

This was also the dividing line for Draco Malfoy. He thought he was very bad, and he had attempted to cast unforgivable curses before. His feeble attempts to murder Dumbledore -- the cursed necklace, the poisoned bottle of mead -- had shown his reluctance to do such a deed: It had to be kept at a remove. When he stood before his intended victim, face to face, he could not bring himself to do it.

Draco was malicious, but he had not surrendered his human dread of murder; he had kept shreds of decency that now tripped him up. And this was so even though it would have been a murder, not simply out of malice, but required in order to save his own life and the lives of his parents. People who are far from evil have chosen to kill under such circumstances. Yet he could not do it. Therefore he was still redeemable.

Consider Snape in this light, and we have no conclusive evidence that he had ever crossed the line into true evil. Not that other characters in the books would agree with that statement. When Harry is discussing Snape's killing of Dumbledore with other members of the Order of the Phoenix, he says, "'Snape passed Voldemort the information that made Voldemort hunt down my mum and dad. Then Snape told Dumbledore he hadn't realized what he was doing, he was really sorry he'd done it, sorry that they were dead.'

"They all stared at him.

"'And Dumbledore believed that?' said Lupin incredulously. 'Dumbledore believed Snape was sorry James was dead? Snape hated James'" (Prince 616).

Nobody in the room argues with Lupin's statement, but Harry himself should have known better than to regard that as a serious answer. Remember that Snape felt a debt to James Potter for having kept him from dying at the hands of a werewolf (Lupin himself, ironically, as recounted in Azkaban), and repaid the debt by repeatedly saving Harry from Quirrell's attempts to kill him in Stone. If Snape felt he owed that debt to James Potter, is it likely he would deliberately have provided Voldemort with information that would provoke him to murder James and Lily? And even if we suppose that Snape actually felt indebted partly because he had indirectly caused James's and Lily's deaths, that still contradicts Lupin's opinion that it was impossible that Snape could be sorry James was dead.

In fact, the whole scene on pages 615 and 616 of Prince consists of people talking each other into a firm belief that Snape had always been deceiving Dumbledore, with no one advancing the possibility that just as Harry had done awful things to Dumbledore at Dumbledore's command, Snape might have killed him for the same reason. It is hardly surprising that they would be unable to make that mental leap, partly because Dumbledore was so newly dead, and partly because they all had disliked, despised, or resented Snape for their own reasons. It seemed to them so much likelier that Snape, a reformed Death Eater, was actually a double agent who had been deceiving even Dumbledore, than that Dumbledore's murder at Snape's hand had been planned from the time that Draco Malfoy was assigned to do the murder.

For that is the only viable alternative explanation for Snape's killing of Dumbledore. When, near the beginning of Prince, Snape takes the Unbreakable Vow to kill Dumbledore himself if Draco could not do it (56), it can be taken at face value, or it can be taken as something Snape agreed to do only because he already knew that it was part of Dumbledore's plan to die.

We can speculate about why Dumbledore might plan such a thing, whether or not he is going to be resurrected: Perhaps he believed that if Voldemort fully believed that Dumbledore was dead, he would act carelessly and prematurely, underestimating the power that resided in Harry because of the purity of the love inside him and all the bonds of love that surrounded him. Perhaps he thought that as long as Harry believed Dumbledore would always bail him out in a crisis, Harry would not prepare himself as intensely as he should for the inevitable confrontation with Voldemort.

Evidence

The only evidence I'm aware of that Snape might have been assigned by Dumbledore to make that Unbreakable Vow and then act on it, killing him on the tower, is deliberately inconclusive. It comes from a conversation between Dumbledore and Snape that was overheard by Hagrid, who reluctantly told Harry about it. Rowling could hardly have made the report more unreliable and less conclusive: Hagrid isn't the best witness, and his telling is distorted by his own desire to minimize the importance of what he heard:

"'Well -- I jus' heard Snape sayin' Dumbledore took too much fer granted an' maybe he -- Snape -- didn' wan' ter do it anymore --'

"'Do what?'

"'I dunno, Harry, it sounded like Snape was feelin' a bit overworked, tha's all -- anyway, Dumbledore told him flat out he'd agred to do it an' that was all there was to it. Pretty firm with him.. An' then he said summat abou' Snape makin' investigations in his House, in Slytherin'" (Prince 405-6).

Hagrid has his own lame theory about what this conversation might have meant, but it's obvious nonsense. But we readers, who know about Snape's Unbreakable Vow to protect Draco and kill Dumbledore if Draco failed to carry out the assignment, can easily see that what Hagrid overheard might have been Snape's insistence that he did not want to carry out the plan to kill Dumbledore, and Dumbledore reminding him that he must do it or die himself. The sentence "You took an Unbreakable Vow" is just the sort of thing that Hagrid might repeat as "Dumbledore told him flat out he'd agreed ter do it an' that was all there was to it."

And the need for Snape to investigate Slytherin House was because Snape had to figure out, without Draco telling him directly, just what his plan for killing Dumbledore was. The fact that Snape did not know it nearly kept him from being in the right place at the right time to fulfil the terms of his Unbreakable Vow and kill Dumbledore.

If this was not the meaning of what Hagrid overheard, then what else could it have been?

After Dumbledore is dead, Harry Potter never thinks of or speaks about what Hagrid overheard. In effect, Rowling drops this information into the middle of a nice thick book, nearly four hundred pages after the taking of the Unbreakable Vow and nearly two hundred pages before the event that the conversation might have anticipated, and none of the characters gives it great significance or brings it up when it might provide an alternate explanation for Snape's behavior. Rowling has played fair with us, she has tipped her hand, but only for a brief moment, in a blur, expecting us to forget it as thoroughly as Harry does, because Hagrid's telling is so confusing that we never hear directly what was actually said.

If the words "Unbreakable Vow" had been said at that point, we would have remembered, and we would know that Snape was trying to get out of killing Dumbledore. The conversation that Hagrid overheard was, in effect, Snape's equivalent of saying, "Let this cup pass from me; nevertheless, thy will, not mine, be done."

In light of that conversation, I believe that we can actually be quite sure that Snape, in killing Dumbledore, was doing his will, exactly as Harry had done Dumbledore's will by forcing him to drink all the liquid in the cave, which is what weakened Dumbledore so much that he could hardly stand when Draco faced him. Obeying Dumbledore tested the moral fibre of his dearest friends -- they had to choose between doing good (i.e., not killing people, not forcing them to drink slow-acting poisons) and being loyal and obedient to him.

What Will Snape Do Now?

Knowing that it was Dumbledore's will that Snape kill him does not tell us much about what Snape will do in the next book. Like Gollum, he is still unpredictable.

After all, Rowling goes to great pains in Prince to show us that Dumbledore is not always right. The locket he nearly died to obtain is not one of Voldemort's four missing horcruxes; he makes other mistakes and admits them. He might have counted on Snape's continuing to obey him and follow his plans after killing him; but will he?

Snape certainly knew Dumbledore's plan up to the point of killing him -- but did he know anything about what Dumbledore intended to do (or have someone else do) after he was dead? Though Snape is a gifted occlumens, that does not mean that Voldemort will never be able to penetrate Snape's mind; therefore it is most likely Dumbledore told Snape nothing more than Snape needed to know.

Thus Snape may now feel himself to be a free agent. Even if he would gladly continue to help Dumbledore accomplish his purposes, he can't do much if he doesn't know what Dumbledore's plans are. He may even conclude that whatever Dumbledore's plan was, it must have failed, and now Snape must make his own accommodation with Voldemort ... or wait for whatever opportunity presents itself, as I suggested before.

What we do know is this: In Snape's last contacts with Harry, he repeatedly saves the boy he despises so much, and gives him advice that is undoubtedly going to be crucial to Harry's surviving or prevailing in his final confrontation with Voldemort: He must learn to hide his thoughts and cast spells without speaking them aloud or even thinking them in such a way that the "most accomplished Legilimens the world has ever seen" might discover them in time to block them (Prince 26).

In Harry Potter and the Half-Blood Prince, Snape is the title character; his vow at the beginning and his murder of Dumbledore near the end frame the story; the book he annotated succeeds in doing what Snape himself could never do in person -- teach Harry to be an accomplished potionmaker. One can argue that despite all distractions, the sixth volume of the series is about Snape.

It is highly unlikely that Rowling would do all this if Snape were not to be important in the final book. Rowling has carefully avoided letting us know, with certainty, just what motivates Snape's actions; but she has also kept Snape from ever crossing the line into evil. Thus we will, in all likelihood, come to the climax of the final book, not knowing what Snape will do in the moment of crisis.

My own prediction is that Snape will reveal himself to be as loyal to Dumbledore as Harry Potter himself; in fact, I go farther, and offer the thought that Rowling will have Snape give his life in the process of helping Harry Potter prevail in the final battle. There are several reasons I believe this -- though I suspect one of the major ones is simply that that is how I, as a novelist myself, would use the character of Snape.

My other reasons for believing this are simple enough:

1. Rowling has built him up so much, in the fifth and sixth volumes, that she must be planning for him to play a major role in the climax of the series.

2. Rowling has laid the groundwork (in Hagrid's report of the overheard conversation) for revealing to Harry that Snape has been loyal to Dumbledore all along.

3. By having Dumbledore refuse to explain his reasons for trusting Snape, Rowling has, in effect, promised us that we will find out the reason, and it will be far more convincing than the lame reasons that the Order of the Phoenix speculates about at the end of Prince.

4. There is no other character whose sacrifice would be so powerful and acceptable to readers. Of course she could have Ron or Hermione or Ginny sacrifice themselves, but they've all been in jeopardy before, and acted nobly, and I think Rowling has no desire to torment her loyal readers like that. As for Harry dying in the process of killing Voldemort -- well, she could do that, but she won't enjoy going through the rest of her life without a single literate person ever speaking to her again.

And aside from those four, there is no character whose noble death would mean as much as Snape's, once his loyalty is revealed. Rowling has set him up for sacrifice.

5. Rowling has made Snape so malicious, so unfair, so vindictive, so cruel to Harry and his friends over the course of the first six volumes that, even though we have been given some justifications for his actions, it would be very difficult for her to bring him through the final confrontation alive -- for she would then have the problem of deciding how Snape and Harry will treat each other after Snape behaves nobly.

What is she going to do, have Snape wash his hair and, now that he doesn't have to act so bad, give Harry a big old hug and say, "I knew you could do it, Harry, my lad!"

Not that there wouldn't be a precedent: At the end of the Star Wars trilogy, George Lucas shows us Darth Vader, a mass murderer and war criminal, so completely redeemed by the act of saving Luke's life that his soul appears as the moral equal of Yoda and Obi-wan, when they all appear to Luke at the Ewok sock hop.

If Lucas can get away with such an absurd moral turnaround, I suppose Rowling can make Snape be nice -- or maybe have him still be a bit snippy but good-at-heart. I think Rowling has more integrity as an artist than Lucas, however, and we'll see no such nonsense. If Snape does live, he will still be Snape.  But I think he will not live.

Snape's offering himself as a noble sacrifice, to save the world from Voldemort and, more specifically, to save the life of the undeserving (in his view) son of one enemy and godson of another, would satisfy Snape's ambition for greatness and recognition and honor. His name would go down in history as one of the greatest of wizards. It's the only motive that would get a Slytherin to act so nobly -- but for that very reason it is true to Snape's character.

Like Gollum in Lord of the Rings, Snape is not the character we are rooting for, but he may be the character whose moral struggle means the most to us in the end. And if, like Gollum, Snape dies in the process of bringing down the Dark Lord, we will feel, not pleasure in Snape's downfall, but a wistful longing that things might have turned out differently for him.