For most of the US, disco died in 1979. Triggered by the infamous "Disco Demolition" night at Comiskey Park in Chicago on July 12, 1979, a backlash made the word "disco" an overnight punchline. Major labels dropped disco artists and producers, and those mainstream musicians who had jumped on the bandwagon just as quickly threw themselves off. Gay men, however, continued to dance, and in the gay enclave of the Castro District in San Francisco, enterprising...