It is one of the great mysteries in the archaeology of the Americas: the depopulation of the northern Southwest in the late thirteenth-century AD. Considering the numbers of people affected, the distances moved, the permanence of the departures, the severity of the surrounding conditions, and the human suffering and culture change that accompanied them, the abrupt conclusion to the farming way of life in this region is one of the greatest disruptions in recorded history.

Much new paleoenvironmental data, and a great deal of archaeological survey and excavation, permit the fifteen scientists represented here much greater precision in determining the timing of the depopulation, the number of people affected, and the ways in which northern Pueblo peoples coped—and failed to cope—with the rapidly changing environmental and demographic conditions they encountered throughout the 1200s. In addition, some of the scientists in this volume use models to provide insights into the processes behind the patterns they find, helping to narrow the range of plausible explanations.

What emerges from these investigations is a highly pertinent story of conflict and disruption as a result of climate change, environmental degradation, social rigidity, and conflict. Taken as a whole, these contributions recognize this era as having witnessed a competition between differing social and economic organizations, in which selective migration was considerably hastened by severe climatic, environmental, and social upheaval. Moreover, the chapters show that it is at least as true that emigration led to the collapse of the northern Southwest as it is that collapse led to emigration.

Research on hunting and gathering peoples has given anthropologists a long-standing conceptual framework of sedentism and mobility based on seasonality and ecological constraints. This work challenges that position by arguing that mobility is a socially negotiated activity and that neither mobility nor sedentism can be understood outside of its social context. Drawing on research in the Mesa Verde region that focuses on communities and households, Mark Varien expands the social, spatial, and temporal scales of archaeological analysis to propose a new model for population movement. Rather than viewing sedentism and mobility as opposing concepts, he demonstrates that they were separate strategies that were simultaneously employed. Households moved relatively frequently--every one or two generations--but communities persisted in the same location for much longer. Varien shows that individuals and households negotiated their movements in a social landscape structured by these permanent communities. Varien's research clearly demonstrates the need to view agriculturalists from a perspective that differs from the hunter-gatherer model. This innovative study shows why current explanations for site abandonment cannot by themselves account for residential mobility and offers valuable insights into the archaeology of small-scale agriculture.