One would be hard-pressed to identify a question of the Soviet past that has been studied with the same intensity over the past few decades as the history of Stalin's Gulag. (1) Thousands of works have been written on the basis of manifold interviews, published memoirs, and documents from both state and private collections. The long list of thoroughly examined topics includes aspects of the Stalinist repressive political apparatus, the structure of the Gulag, the functioning of its administrative bureaucracy from the lowest rungs to the central leadership, and the principles undergirding forced labor and camp life. Many data concerning the magnitude of the camp system, its population, and indicators of production have been published and circulated. Scholars are investigating key moments in the history of the Gulag, such as prisoner uprisings. Increasingly, the object of study has become various aspects of Gulag society itself. (2) The historiography of the Gulag is, broadly speaking, approaching the point at which we merely begin to reproduce or touch up a well-illustrated picture; one now senses a pressing need to reconsider the literature with the aim of identifying lacunae and new directions for research. Indeed, the advent of new approaches for studying the Gulag is to some extent predicated on the development of new source bases. (3) At the same time, the archival revolution has inevitably contributed to ever-growing specialization, and therefore much will still depend on our ability to sharpen our perspective on the most fundamental questions and problems of Gulag scholarship. The present article is intended to highlight several complex questions regarding the Gulag's history. In particular, I draw attention to the task of defining the Gulag's boundaries, identifying the channels of its interaction with the broader Soviet society, and specifying the consequences of these interactions in both short- and long-term perspective. Such questions are not entirely novel; one need only recall Alexander Solzhenitsyn's journey through implicitly bounded circles of the Gulag hell or his conception of the Soviet world as bifurcated between greater and lesser zones. (4) At the same time, as they bring to bear previously unknown facts and new methods, historians are in a position to refine and even to challenge established perspectives, or at the very least to articulate new directions for research. Defining Boundaries Recent work has contributed to a vivid and compelling picture of Soviet society under Stalin as composed of several interrelated layers. The first is the Gulag itself--a flourishing system of camps, colonies, prisons, special settlements, and other more fleeting and specialized units of isolation and forced labor. The preponderance of available data indicates that between 1930 and 1952, nearly 25 million people passed through the Gulag system, 18-20 million of whom were sentenced to imprisonment in camps, colonies, and prisons. (5) Meanwhile, no fewer than six million people, mostly kulaks and members of repressed nationalities, were sent into internal exile, living under conditions approaching those of the camps themselves in special settlements. (6) In addition, World War II saw several million Soviet citizens interned, quarantined, or subjected to forced labor. The Gulag population was notable for its diversity and for an internal hierarchy that mirrored the hierarchy of Soviet society beyond the Gulag. There were inversions as well: political prisoners, many of whom occupied high positions outside the Gulag, frequently found themselves at a much lower level on the Gulag's social ladder, often yielding to common criminals. (7) The world of special settlements was similarly diverse. The groups most typically liable to deportation included peasants, Baltic and Ukrainian partisans, persecuted peoples of the North Caucusus, and city dwellers expelled during the passportization process. …