The document provides an overview of science fiction movies from the 1950s in the United States. It discusses how the films reflected the post-war fears around communism and nuclear technology. The movies featured alien invasions as metaphors for communist threats and scientists causing mutations through atomic experiments. It summarizes some of the most popular subgenres and examples like The War of the Worlds and Them!. It also describes common character archetypes and provides a timeline and analysis of special effects innovations as well as opinions on the best and worst films of the genre.