What I like about not writing original material — which I’m not even certain I could do — is that you have this tremendous advantage of reading something for the first time. You never have this experience again with the story. You have a reaction to it: it’s a kind of falling-in-love reaction.
That’s the first thing. Then it becomes almost a matter of code breaking, of breaking the work down into a structure that is truthful, that doesn’t lose the ideas or the content or the feeling of the book. And fitting it all into the much more limited time frame of a movie.
And as long as you possibly can, you retain your emotional attitude, whatever it was that made you fall in love in the first place. You judge a scene by asking yourself, “Am I still responding to what’s there?” The process is both analytical and emotional. You’re trying to balance calculating analysis against feeling. And it’s almost never a question of “What does this scene mean?” It’s “Is this truthful, or does something about it feel false?” It’s “Is this scene interesting? Will it make me feel the way I felt when I first fell in love with the material?” It’s an intuitive process, the way I imagine writing music is intuitive. It’s not a matter of structuring an argument.
-Stanley Kubrick on adapting books to the screen.