Half a century now separates us from the Great Purges of 1936–8. Yet the causes of these political persecutions remain obscure, for many key sources for the study of the purges are only now beginning to be explored in any systematic fashion by historians. The manner in which scholars have traditionally approached the Great Purges accounts for the failure to explore thoroughly all available sources. Until recently, the Great Purges have been studied from the top down, from the vantage point of the apex of the Soviet political system, usually with an emphasis on the role of Soviet dictator Joseph Stalin, to whose personal predilections and political needs the purges have often been exclusively attributed.

Thus viewed, available source materials on the purges were rapidly exhausted, since the archives of the higher councils of the Communist party were closed until quite recently to scholars. Stalin's few public pronouncements at the time of the Great Purges, which is all we had to go on before the Central Party Archives became freely available to researchers, offered little insight into the causes of the purges or Stalin's own role in these events. As a result, scholars tended to rely for large part on sources not generally accepted by historians, like rumor, gossip, and second- and third-hand accounts of developments within the Kremlin, even those of individuals who were outside the USSR altogether at the time of the Great Purges.