Organized in the mid-1970s as a means of communal protection against livestock rustling and general thievery in Peru’s rugged northern mountains, the rondas campesinas (peasants who make the rounds) grew into an entire system of peasant justice and one of the most significant Andean social movements of the late twentieth century. Nightwatch is the first full-length ethnography and the only study in English to examine this grassroots agrarian social movement, which became a rallying point for rural pride. Drawing on fieldwork conducted over the course of a decade, Orin Starn chronicles the historical conditions that led to the formation of the rondas, the social and geographical expansion of the movement, and its gradual decline in the 1990s. Throughout this anecdotal yet deeply analytical account, the author relies on interviews with ronda participants, villagers, and Peru’s regional and national leaders to explore the role of women, the involvement of nongovernmental organizations, and struggles for leadership within the rondas. Starn moves easily from global to local contexts and from the fifteenth to the twentieth century, presenting this movement in a straightforward manner that makes it accessible to both specialists and nonspecialists. An engagingly written story of village mobilization, Nightwatch is also a meditation on the nature of fieldwork, the representation of subaltern people, the relationship between resistance and power, and what it means to be politically active at the end of the century. It will appeal widely to scholars and students of anthropology, Latin American studies, cultural studies, history, subaltern studies, and those interested in the politics of social movements.