China’s vast new cities have been built by millions of migrant construction workers from the countryside, who labor without contracts, fringe benefits, or injury compensation. In this closely observed and empathetic account, Swider describes three types of labor arrangements. Some migrants sign up for a year at a time with trade-specialized teams that work for big contractors, moving among construction sites and never making contact with the urban society around them. Others do piecework in smaller, mixed-trade groups put together by relatives or people from their home provinces. They may bring their families to live in migrant ghettos in the cities, but under China’s hukou (household registration) system, they never acquire legal status as urban residents. Under a third type of arrangement, migrants pick up menial day jobs at “black labor markets,” risking physical abuse and taking their chances on getting paid. All these jobs are temporary. But in the construction field, the institution of temporary labor appears to be permanent. The workers are too fragmented and vulnerable to challenge the system.