James Caesar Petrillo, President of the American Federation of Musicians, called a strike effective July 31, 1942, prohibiting union members from making any disc recordings or electrical transcriptions. The present study recounts the history of that strike, including efforts to end it, reactions to it by various government and trade organizations and the circumstances under which it finally did end. The study focuses on the effect of the strike on radio broadcasters, both directly (through recordings they used) and indirectly (through the strike's effects on the recording and related industries), and concludes that it changed the character of radio's music somewhat, but had little detrimental effect on radio's profits.