Using material from the papers of Dalton Trumbo, Dore Schary, Melvyn Douglas and other Hollywood insiders, Ronald and Allis Radosh trace the growth of the Communist Party from the 1920s, when stars like Charlie Chaplin and Groucho Marx toured the Soviet Union and came back converted, through the 1930s and the war years, when the Party achieved critical mass in Hollywood. The Radoshes’ most controversial discovery is that during the investigations of the House Committee on Un-American Activities, while others were lionizing them as blameless victims of a vicious blacklist, the Hollywood Reds themselves were beset by doubts and disagreements about their disloyalty to America and their treatment by the Communist Party. Red Star over Hollywood opens up the cells and discussion groups that defined Hollywood radicalism.