Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The organization of the Communist Party of the Soviet Union was based on the principles of democratic centralism. The governing body of the CPSU was the Party Congress which initially met annually but whose meetings became less frequent, particularly under Stalin. Party Congresses would elect a Central Committee which, in turn, would elect a Politburo. Under Stalin the most powerful position in the party became the General Secretary who was elected by the Politburo. In 1952 the title of General Secretary became First Secretary and the Politburo became the Presidium before reverting to their former names under Leonid Brezhnev in 1966.