With rapid commercialization, a booming urban economy, and the relaxation of state migration policies, over 100 million peasants, known as China s floating population, have streamed into large cities seeking employment and a better life. This massive flow of rural migrants directly challenges Chinese socialist modes of state control. This book traces the profound transformations of space, power relations, and social networks within a mobile population that has broken through the constraints of the government s household registration system. The author explores this important social change through a detailed ethnographic account of the construction, destruction, and eventual reconstruction of the largest migrant community in Beijing. She focuses on the informal privatization of space and power in this community through analyzing the ways migrant leaders build their power base by controlling housing and market spaces and mobilizing social networks.