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Screenwriting Books Worth Having
By an Amazon.com customer
The Screenwriter's Bible: A Complete Guide to Writing, Formatting, and Selling Your ScriptThe Screenwriter's Bible: A Complete Guide to Writing, Formatting, and Selling Your Script by David Trottier
Buy new: $15.61 / Used from: $10.99
The very best overall survey of screenwriting, from craft to business.
Screenplay: Writing the PictureScreenplay: Writing the Picture by Robin U. Russin
Buy new: $14.93 / Used from: $11.00
For an excellent, more detailed analysis of the process of screenwriting.
How Not to Write a Screenplay: 101 Common Mistakes Most Screenwriters MakeHow Not to Write a Screenplay: 101 Common Mistakes Most Screenwriters Make by Denny Martin Flinn
Buy new: $11.53 / Used from: $7.50
Use this after you've done some writing.  It will help you sharpen your critical eye.
Secrets of Film WritingSecrets of Film Writing by Tom Lazarus
Buy new: $11.66 / Used from: $3.87
This is your third or fourth book, once you've done some writing and understand better how a screenplay works.
Alone in a RoomAlone in a Room by John Scott Lewinski
Buy new: $15.56 / Used from: $0.40
Some say you should read this first, but I disagree.  Read after you've written a script or two.  It will make much more sense.
The Writers Journey: Mythic Structure for Writers, 2nd EditionThe Writers Journey: Mythic Structure for Writers, 2nd Edition by Christopher Vogler
Buy used from: $3.40
A very nice and concise distillation of Joseph Campbell's Heroic Structure
The Hero with a Thousand Faces (Bollingen Series, No. 17)The Hero with a Thousand Faces (Bollingen Series, No. 17) by Joseph Campbell
Buy used from: $4.49
The Man himself, if Vogler's version wasn't good enough for you.
The Declaration of Independent Filmmaking: An Insider's Guide to Making Movies Outside of HollywoodThe Declaration of Independent Filmmaking: An Insider's Guide to Making Movies Outside of Hollywood by Mark Polish
Buy new: $11.70 / Used from: $0.01
The makers of Northfork give you an overview of moviemaking, which writers should understand
Rebels on the Backlot: Six Maverick Directors and How They Conquered the Hollywood Studio System (P.S.)Rebels on the Backlot: Six Maverick Directors and How They Conquered the Hollywood Studio System (P.S.) by Sharon Waxman
Buy new: $11.69 / Used from: $4.00
A little uneven, but excellent glimpse of Hollywood and how great movies get made.
Pulp FictionPulp Fiction by Quentin Tarantino
Buy new: $12.95 / Used from: $0.03
Reading screenplays is critical.  This for incredible dialogue
Good Will Hunting: A ScreenplayGood Will Hunting: A Screenplay by Ben Affleck
Buy new: $11.95 / Used from: $0.13
This for character creation and story
The Truman Show: The Shooting ScriptThe Truman Show: The Shooting Script by Andrew Niccol
Buy new: $11.53 / Used from: $2.99
This for concept and character
FargoFargo by Joel Coen
Buy used from: $2.99
This is one of the most perfect, simple movies ever made.