"Book-to-screen adaptations must always strive for two things: First, you must find a way to tell the broad story of the original plot; second, you must somehow reflect the spirit and texture of the novel—that is, you must transform a lot of words into a few pictures. All those digressions, inner monologues, thought processes, turns of phrase, all those word pictures, and especially all that un-photographable stuff that made the novel so delicious, must somehow be represented onscreen by use of the filmmaker's tools: moving pictures, dialogue and performance, sets, costumes, music and all the other tricks of the trade. That's the process a writer must go through to create a successful blueprint for a film."
January 1, 1970
https://en.wikiquote.org/wiki/Tommy_Lee_Wallace