Answer:

Impossible to list all the authors that have written books that matter greatly to me. But let me list a few that were important to me prior to beginning my writing career:

Sci-fi

• Heinlein
• Norton
• Asimov
• Clarke
• Bradbury
• LeGuin
• Ellison
• Blish

Fantasy

• Tolkien
• Lewis
• George Macdonald
• Mary Stewart (the Merlin books)
• T.H. White

Children's

• E.B.White
• Lawson (Rabbit Hill)
• Altsheler (Civil War and French&Indian War novels)

Historical

• Elswyth Thane (Williamsburg novels)
• Mitchell
• Nordhoff & Hall (Bounty trilogy)
• Forrester (Hornblower)
• Taylor Caldwell
• Wallace (Ben-Hur)

Mystery

• Christie
• Wolfe
• du Maurier
• Ross MacDonald

Mainstream

• Joseph Smith (Book of Mormon)
• Shakespeare (the plays)
• Twain (Prince & the Pauper, Tom Sawyer)
• Austen
• Douglas (The Robe; Forgive Us Our Trespasses)
• Albee (Virginia Woolf)
• William Goldman (Boys & Girls Together)
• Rand (Fountainhead)
• Wilde (Ernest)
• James Goldman (A Lion in Winter)
• Arthur Miller (All My Sons; Crucible)
• O'Neill
• Michener (Source; Tales of the South Pacific)

Nonfiction

• Shirer (Rise & Fall of the Third Reich)
• Plato
• Bruce Catton (Army of the Potomac)
• William Manchester

Poetry

• Hopkins
• Dickinson
• Cummings
• Shakespeare
• Halleck
• Jonson
• Tennyson
• Yeats
• Auden

All these represent readings prior to my beginning to write seriously, and this list is by no means complete, especially in the nonfiction area, where I was rarely aware of authors and simply absorbed information.

Authors now working whose works I look forward to and buy instantly are:

• Dave Wolverton / David Farland
• Robin Hobb / Megan Lindholm
• Robert Parker
• Sue Grafton
• Sharyn McCrumb
• Lisa Goldstein
• Octavia Butler
• George R.R. Martin
• Walter Mosley
• Robert Caro
• Stephen Pinker
• Lehane
• Burke
• Crais
• McBain
• Connelly
• Block
• Cormier
• Sleator

Again, this is far from exhausting the list.