Stalin’s death in 1953 ushered in the so-called ‘collective leadership’ in the Soviet Union, which was really a polite covering term for the struggle between Stalin’s heirs for supreme power in the party and state. This comprised in part genuine differences of opinion on questions of policy, but also clashes between personalities and interest groups. To the political historian Soviet events present much the same problems as medieval history. The sources are complicated by the fact that the most valuable Soviet data did not appear directly after the events took place, but much later and in isolated fragments. Far more disturbing from the scholar’s point of view is the suspicion that some of the source material consists of suppression of the truth or else open lies. Whole episodes of Soviet history have been distorted and even suppressed completely in such important sources as the Great Soviet Encyclopaedia.