Also well worth a read:

Writing Television Drama by Nicholas Gibbs

Writing Movies for Fun and Profit by Thomas Lennon & Robert Ben Garant

The Complete Book of Scriptwriting by J Michael Straczynski

Essential Reading for Screenwriters:

Poetics by Aristotle

The Hero with a Thousand Faces by Joseph Campbell

The Writer’s Journey: Mythic Structure for Writers by Christopher Vogler

Screenplay: The Foundations of Screenwriting by Syd Field

Story by Robert McKee

Save the Cat! by Blake Snyder

The 21st Century Screenplay by Linda Aronson

Doctor Who: The Writer’s Tale: The Final Chapeter by Russell T Davies and Benjamin Cook

The Insider’s Guide to Writing for Television by Julian Friedmann and Christopher Walker