Book excerpt: This book brings together the research into regional development and social change carried out in highland Peru by a team of British and Latin American social anthropologists and sociologists. The area studied—the Mantaro Valley of central Peru—is one of the most densely populated and economically differentiated of highland zones; it is also notable for its community-based forms of cooperation and its high level of peasant political activity. The book presents a series of case studies that examine cooperative forms of organization in relation to developments in the regional economy and to changes in national policy. The analysis attempts to avoid interpreting local processes merely as responses to externally initiated change. It stresses instead the need to consider the interplay of local and national forces, because local groups and processes themselves affect the pattern of regional and national development. The case studies cover a range of political and economic topics, from peasant movements to the achievements and shortcomings of government-sponsored agricultural and manufacturing cooperatives. The concluding chapter, by the editors, explores the theoretical implications of these studies.