Since revolutions are complex social and political upheavals, historians who write about them are bound to differ on the most basic questions--causes, revolutionary aims, impact on the society, political outcome, and even the timespan of the revolution itself. In the case of the Russian Revolution, the starting-point presents no problem: almost everyone takes it to be the "February Revolution" of 1917, which led to the abdication of Nicholas II and the formation of the Provisional Government. But when did the Russian Revolution end? Was it all over by October 1917, when the Bolsheviks took power? Or did the end of the Revolution come with the Bolsheviks' victory in the Civil War in 1920? Was Stalin's "revolution from above" part of the Russian Revolution? Or should we take the view that the Revolution continued throughout the lifetime of the Soviet state?

In his Anatomy of Revolution, Crane Brinton suggested that revolutions have a life cycle passing through phases of increasing fervor and zeal for radical transformation until they reach a climax of intensity, which is followed by the "Thermidorian" phase of disillusionment, declining revolutionary energy, and gradual moves towards the restoration of order and stability. The Russian Bolsheviks, bearing in mind the same French-Revolution model that lies at the basis of Brinton's analysis, feared a Thermidorian degeneration of their own Revolution, and half suspected that one had occurred at the end of the Civil War, when economic collapse forced them into the "strategic retreat" marked by the introduction of the New Economic Policy (NEP) in 1921.

Yet at the end of the 1920s, Russia plunged into another upheaval--Stalin's "revolution from above," associated with the industrialization drive of the First Five-Year Plan, the collectivization of agriculture, and a "Cultural Revolution" directed primarily against the old intelligentsia--whose impact on society was greater even than that of the February and October Revolutions of 1917 and the Civil War of 1918-1920. It was only after this upheaval ended in the early 1930s that signs of a classic Thermidor can be discerned: the waning of revolutionary fervour and belligerence, new policies aimed at restoring order and stability, revival of traditional values and culture, solidification of a new political and social structure. Yet even this Thermidor was not quite the end of the revolutionary upheaval. In a final internal convulsion, even more devastating than earlier surges of revolutionary terror, the Great Purges of 1937-8 swept away many of the surviving Old Bolshevik revolutionaries, effected a wholesale turnover of personnel within the political, administrative, and military elites, and sent more than a million people (by latest counts) to their deaths or imprisonment in Gulag.

In deciding on a timespan for the Russian Revolution, the first issue is the nature of the "strategic retreat" of NEP in the 1920s. Was it the end of the Revolution, or conceived as such? Although the Bolsheviks' avowed intention in 1921 was to use this interlude to gather strength for a later renewal of the revolutionary assault, there was always the possibility that intentions would change as revolutionary passions subsided. Some scholars think that in the last years of his life, Lenin (who died in 1924) came to believe that for Russia future progress towards socialism could only be achieved gradually, with the raising of the cultural level of the population. Nevertheless, Russian society remained highly volatile and unstable during the NEP period, and the party's mood remained aggressive and revolutionary. The Bolsheviks feared counter-revolution, remained preoccupied with the threat from "class enemies" at home and abroad, and constantly expressed their dissatisfaction with NEP and unwillingness to accept it as the final outcome of the Revolution.

A second issue that has to be considered is the nature of Stalin's "revolution from above" that ended NEP in the late 1920s. Some historians reject the idea that there was any real continuity between Stalin's revolution and Lenin's. Others feel that Stalin's "revolution" does not deserve the name, since they believe it was not a popular uprising but something more like an assault on the society by a ruling party aiming at radical transformation. In this book, I trace lines of continuity between Lenin's revolution and Stalin's. As to the inclusion of Stalin's "revolution from above" in the Russian Revolution, this is a question on which historians may legitimately differ. But the issue here is not whether 1917 and 1929 were alike, but whether they were part of the same process. Napoleon's revolutionary wars can be included in our general concept of the French revolution, even if we do not regard them as an embodiment of the spirit of 1789; and a similar approach seems legitimate in the case of the Russian Revolution. In common-sense terms, a revolution is coterminous with the period of upheaval and instability between the fall of an old regime and the firm consolidation of a new one. In the late 1920s, the permanent contours of Russia's new regime had yet to emerge.

The final issue of judgement is whether the Great Purges of 1937-8 should be considered a part of the Russian Revolution. Was this revolutionary terror, or was it terror of a basically different type--totalitarian terror, perhaps, meaning a terror that serves the systemic purposes of a firmly entrenched regime? In my view, neither of these two characterizations fully describes the Great Purges. They were a unique phenomenon, located right on the boundary between revolution and postrevolutionary Stalinism. This was revolutionary terror in its rhetoric, targets, and snowballing progress. But it was totalitarian terror in that it destroyed persons but not structures, and did not threaten the person of the Leader. The fact that it was state terror initiated by Stalin does not disqualify it from being part of the Russian Revolution: after all, the Jacobin Terror of 1794 can be described in similar terms. Another important similarity between the two episodes is that in both cases the primary targets for destruction were revolutionaries. For dramatic reasons alone, the story of the Russian Revolution needs the Great Purges, just as the story of the French revolution needs the Jacobin Terror.