Most screenplay books clean up the screenplay.
They're typeset into neat lettering on clean pages, and you're never sure if anything has been cut out or not. The worst screenplay books I've ever seen are Woody Allen's, which simply transcribe the finished movie in print. It's sloppy, but perfect. You feel as if Sturges is in the room with you. And, best of all, the scenes that didn't make the final cuts of the films are still intact.