This is the first major study by a Russian Marxist historian of the most tragic and fateful year in the history of the Soviet Union. With an encyclopedic knowledge of Soviet source material, including archival documents released after the fall of the USSR, Vadim Rogovin presents a detailed and penetrating analysis of the causes, impact and consequences of Stalin's purges. He demonstrates that the principal function of the terror was the physical annihilation of the substantial socialist opposition to Stalin's bureaucratic regime.