The Writer’s Journey: Mythic Structure for Writers (Christopher Vogler)
Chris Vogler is a development guru that has worked for Disney studios, Fox 2000 pictures, and Warner Bros. He has also taught at USC, Division of Animation and Digital Arts, and through the UCLA extension courses.
This is the definitive book that takes mythology and The Hero’s Journey and melds it into the context of screenwriting. If you’re writing a hero-based fantasy, action, or adventure script, it’s a must read. However, the hero’s journey isn’t applicable to all screenplays and protagonists.
Like any dictated formula or story structure theory, there is no one true answer and it often seems like many screenwriters treat this book and others as such. This is just one of the structures that you can either fully employ, or adapt to whatever you already have floating around in your mind.
Regardless, there is a plethora of great information that you can apply to your own stories and protagonists.