No single episode did more to set off alarms of a diabolic “Red” conspiracy within the national government than the case of Alger Hiss. In the midst of the 1948 presidential campaign, the House Un-American Activities Committee conducted a hearing in which Whittaker Chambers, a senior editor at Time magazine and former Soviet agent who had broken with the communists in 1938, identified Hiss, who had worked as an aide to the assistant secretary of state, as an underground party member in the 1930s. This file traces the many figures involved in one of the era’s most famous witch hunts. Trails of evidence are followed through correspondence between alleged Communist Party members and sympathizers, as well as interviews with associates of the accused. The archive is an invaluable resource on the Second Red Scare and the internal politics of the United States during the early years of the Cold War.