The list author says: "There are hundreds and hundreds of screenwriting books out there. This is not a list to teach you to "Save The Cat" or to "Write a Screenplay in 21 Days." Those kind of books are for beginners and wanabees.
This is a list of the books most often recommended at USC's School of Cinematic Arts. These are books for the serious screenwriter who wishes to elevate his or her craft."
"This book is based on the work of Frank Daniel. He was a legendary Dean of the Cinema School at USC for many years and taught throughout the country. His students and protegees include Milos Forman and David Lynch. (http://en.wikipedia.org/wiki/Frank_Daniel) Paul Gulino, the author, went to USC and studied with Daniel."
"This is not a book on screenwriting in particular, but it applies to the gut-wrenching and mysterious writing process in any medium. Again, a must-read for the serious screenwriter, especially as you face writer's block, frustration and despair."