Fraser M. Ottanelli examines the history of the Communist Party of the United States (CPUSA) from the stock market crash to the reconstitution of the Party in 1945. He explains the appeal of the CPUSA and its emergence as the foremost vehicle of left-wing radicalism during these years. Most studies of the CPUSA have focused on either the grass-roots activities of the Party's members or the Party's relations with the Communist International in Moscow. For the first time, Ottanelli explores in depth the subtle and intricate interaction between these two levels. During the '30s and '40s, the policies of the CPUSA were influenced as much by the Party's involvement in national social and labor struggles as they were by Moscow. Party leaders attempted to set policy that would be relevant to American society. Ottanelli looks at the Party's domestic policies and activities concerning labor, race, youth, the unemployed, as well as the Party's changing attitude toward FDR and the New Deal, its policies in foreign affairs, and war-time activities. For most of the period under study, Communists increased in strength, influence, relative acceptance, and their ability to make significant contributions to labor and social struggles. Ottanelli attributes these accomplishments to the Party's search for policies, language, and organizational forms that would adapt radicalism to the unique political, social, and cultural environment of the United States.