Sidney Lumet on theme

The question “What is this movie about?” will be asked over and over again throughout the book. For now, suffice it to say that the theme (the what of the movie) is going to determine the style (the how of the movie)… I work from the inside out. What the movie is about will determine how it will be cast, how it will look, how it will be edited, how it will be musically scored, how it will be mixed, how the titles will look, and, with a good studio, how it will be released.

— from Making Movies by Sidney Lumet