During the decade, the central government in Nanjing was dominated by Chiang Kai-Shek, and a central feature of his Nationalist program was the establishment of a special Chinese municipality in Shanghai. Members of the secret police represented the primary instrument of the Nationalists for imposing their revolutionary political order on China's largest urban city. Nonetheless, a criminal underworld existed that included casino and brothel owners, racketeers, drug syndicates, gun runners, underground Communist assassins, and Comintern secret agents. The author examines the role of the secret police in terms of developing new policing techniques and responding to organized crime and in terms of the implications of political choices for policing. Appendixes contain additional information on Public Security Bureau regulations on lotteries, the Shanghai Peace Preservation Corps, and the effect of the Great Depression on Shanghai police. References, notes, tables, and figures