This compelling work of documentary history tells a story of idealism betrayed, a story of how the Comintern (Communist International), an organization established by Lenin in 1919 to direct and assist revolutionary movements throughout the world, participated in, and was ultimately destroyed, by the Stalinist repression in the late 1930s. Presenting and drawing on recently declassified archival documents, William J. Chase analyses the Comintern's roles as agent, instrument, and victim of terror. In both principle and practice, the Comintern was an international organization, with a staff that consisted primarily of Communist emigres who had fled dictatorial regimes in Europe and Asia. It was, however, headquartered in Moscow and controlled by Soviet leaders. This book examines the rise of suspicions and xenophobia among Soviet and Comintern leaders and cadres for whom many foreigners were no longer the heroes of the class struggle but rather possible enemy agents. Some Comintern members internalised and acted on Stalin's theories about the infiltration of foreign spies into Soviet society, supplying the Soviet police with information that led to the exile or execution of emigres. Thousands of other emigres also became victims of the purges. Together the text and documents of this book convey graphically the essential roles played by the Comintern, providing a unique perspective on the era of Stalinist repression and terror.