By interweaving narrative and documents, the authors of this book present a picture of the Communist Party of the United States of America (CPUSA), one of the most controversial organizations in American public life. Heated debates about whether the Communist Party harboured spies or engaged in espionage have surrounded the party from its inception. This book provides proof that the CPUSA was involved in various subversive activities. At the same time, it discloses details about the workings of the party and about the ordinary Americans and CPUSA leaders who participated in its clandestine activities. The documents presented range from letters by Americans wishing to do international covert work for the Soviet Union, to top secret memos between the head of Soviet foreign intelligence, the Comintern and the CPUSA. They confirm that: the Soviet Union heavily subsidised the CPUSA and that some prominent Americans laundered money for the Comintern; the CPUSA maintained a covert espionage apparatus in the United States with direct ties to Soviet intelligence; the testimony of former Communists concerning underground Communist activity in the United States can be substantiated; American Communists working in government agencies stole documents and passed them to the CPUSA, which sent them on to Moscow; and the CPUSA played a role in atomic espionage. A narrative places the documents in their historical context and explains key figures, organizations and events. Together the narrative and documents provide a picture of American communism and convey the contradictory passions that drew so many Americans into the Communist movement and eventually tore that movement apart.