Conventional wisdom has long held that the Maoist system of totalitarianism differed from its Soviet and Eastern European counterparts by relying solely on the mobilized masses to very publicly dispense terror, rather than on a system of covert informants. That turns out to be wrong. Schoenhals discovered piles of documents in flea markets and used bookshops that reveal an extensive citizen-agent apparatus at work in urban areas under the direction of the Ministry of Public Security. The agents were originally supposed to target enemy spies, saboteurs, and subversives but were soon turned against people with bad “class backgrounds,” citizens failing to show sufficient political enthusiasm, members of minority ethnic groups, and random targets unlucky enough to attract attention. The materials Schoenhals has collected focus chiefly on the bureaucratic processes of recruiting, training, and running agents. The impact of the surveillance on society remains to be studied. Schoenhals ends the story in 1967, when the system was disbanded during the factional struggles of the Cultural Revolution. But there is reason to believe that it has since been restored and expanded.