The film, narrated by "LA Plays Itself" director Fred Halstead, begins by looking at the muscle magazines and films of the late 1940s-early 1960s, then at the softcore films of the late 60s and the boundary-pushing and legal-testing which allowed these to evolve into hardcore loops and then features.
Streaming and downloads are provided by third-party sources. If one doesn't work, try another source above.
