How do private individuals secure social cooperation in China’s illegal markets? This book project examines, both theoretically and empirically, the formation of various categories of extralegal governance institution and the ways in which private individuals, companies, and organizations utilize them to facilitate social cooperation and economic exchange in illegal economies. It adopts a multiple-case study design comprising four cases: street vending, small-property-right housing, corrupt exchanges, and online loan sharks. The cases are purposively selected to sample China’s illegal markets, which ranges from offline to online, from public sectors to private sectors, and from socially acceptable to socially unacceptable. This book project advances understanding of extralegal governance in authoritarian China, where private property rights are ambiguously defined, the judicial system is weak, public sector corruption is still problematic, and illegal markets flourish.