Hollywood films from the 1930s through the 1950s reflected their era-and sometimes created it. Today, classic films are the moving image scrapbooks of collective memory, but when they were shown long ago in downtown movie palaces or neighborhood second-run movie houses, they were, as much as the newsreels, a catalogue of current events. Movies in Our Time - Hollywood Mirrors and Mimics the Twentieth Century is a collection of thoughtful, humorous,...