The BKP in 1973 was structured very much like the Communist Party of the Soviet Union. The structure is pyramidal in form, the general membership making up the base and the office of first secretary occupying the apex. Between the two extremes the most important bodies from bottom to top are the Party Congress, the Central Committee, the Secretariat, and the Politburo. The Party Congress is a large gathering of delegates, representing the rank and file, that meets every five years, theoretically, to make party policy, amend party statutes if necessary, and determine the party program for the ensuing five-year period. Actually the congress is a large, unwieldy body (over 1,500 delegates at the 1971 congress), which meets to demonstrate solidarity rather than to make policy. The congress, by party statute, elects the Central Committee, which is a permanently sitting body that acts in the name of the congress during the long intervals when the larger body is not in session. The so-called election of the Central Committee is, in fact, a ratification of preselected members. The same holds true for the election of the Politburo and the Secretariat by the Central Committee--in effect, the Politburo has already determined its own membership and that of the Secretariat, and the election process by the Central Committee is unanimous confirmation rather than election, making the Politburo a self-perpetuating body. The Politburo for policymaking and the Secretariat for policy implementation are the true centers of power in the overall party-government system. The Central Committee is an operating body and is made up of important members of the party, although they rank below the small group that has reached the top echelons of the structure. It is the interlocking of various party and government positions that really concentrates power in the hands of a few individuals and permits the ultimate leader, Zhivkov, to control the entire apparatus. Zhivkov himself is an example of the interlocking in that, since 1971, he has been the first secretary of the party and a member of the Politburo at the same time that he was the president of the governmental State Council. Only one other individual in 1973 combined membership in the party's most prestigious bodies--Politburo and Secretariat--with membership in the government's leading body--the State Council. Two other party secretaries were candidate (nonvoting) members of the Politburo, but they did not concurrently hold any high government office.