Don't read the book first
Rewriting/adapting a novel into a screenplay is tremendous work. In novels, there is so much subtlety and texture (if done correctly) that a person can end up either marginalizing important points, or carving out too much of it altogether.
Having written 2 adaptions of Philip K Dick short stories (both in public domain), I can attest that short stories work much better for adaptions. I had to add in about 35% new material for each story, but they were stronger in the end. I am sure PKD would have approved.
Now I am adapting my own 65,000 word novel to a screenplay, and its hurts. I have to squeeze the essence of a 65k masterpiece into approximately 25,000 words. Entire subplots have to go. Subtle nuances are erased. But in the end I have to remember that I am trying to capture the essence of the story, not the totality of it.
In the cinematic world, we have two excellent examples of how this is done well, and how it is done poorly. The novels are “The Guns of Navarone” by Alistair MacLean, and “The Bourne Identity” by Robert Ludlum. Both action novels, and both expertly crafted. But their transformations into the cinematic world are as different as socialism and capitalism.
The film “Guns of Navarone” is a masterpiece of cinematic work. It runs at around 2.5 hours and barely feels half that long. It’s gripping, edgy and exciting. Having Gregory Peck and Anthony Quinn as stars didn’t hurt. But that movie managed to capture the exhilaration and edge of the novel, while not following the book scene for scene. It’s an enjoyable action-fest for the uninitiated. Watch the movie, then read the book. You’ll be glad for both.
Conversely, it does not matter whether you read the book first or see the movie, you will be gravely disappointed watching “The Bourne Identity”. I suppose if you never knew the book existed (which was probably 90% of the movie going public), you would think Identity was an action-packed thrill fest. What marred the movie so badly was the elimination of half of the main plot: that Jason Bourne was being hunted at every turn by Carlos the Jackal (a real life assassin btw) in his search for the keys to who he really is.
Ludlum’s book was a tense page turner, spectacularly penned to keep you reading. Bourne the movie is a cheesecake fest with car chases and explosions bogging it down to the point of banality. Add to that, Marie’s character is a B.A. in her own right in Ludlum’s version, and she has quite a bit to do with keeping Bourne alive. The movie Marie is, well…. yawn.
Having done it, I can say it’s tough work. Having seen Guns, I can say that it can be done well. Other “Well Dones” go out to “Bladerunner/Do Andoids dream of Electric Sheep”, “The Maltese Falcon”, and “The Princess Bride”.
It can be done. And so I tell myself: back to work.