This is one of the best books I've read about movies in a few years. Prince looks at the PCA papers for movies from the early talkies to the start of the "ratings system" in the Sixties. He looks at how the films depicted violence, and how they got into trouble with the Code Authority. (Prince doesn't use the word censor, and he shows he has a valid point for this.)
The result is simply eye-opening. It will make you want to see Frankenstein, The Public Enemy, Scarface (1931) and G-Men again. Prince shows how the PCA was especially troubled by violence in horror and gangster films and by edge weapons more than guns. He also shows how "film noir" was a sustained assault on the conventions of screen violence handed down in the Thirties. (Oddly, Prince hardly uses the term "film noir" although the films he mentions: The Glass Key, Brute Force, Kiss Me Deadly, are all from the noir canon.)
Not only does Prince tell the history of American screen violence, but he analyzes the techniques by which filmmakers depicted violence. He never becomes dry or academic as he discusses these films.
Strongly recommended for anyone with an interest in the horror film, gangster movies or film noir.