During World War II, the Soviet leader Joseph Stalin backed away from a policy of ruthlessly suppressing religion and adopted a more tolerant approach. Based on newly available sources in many languages, including Persian, Tatar, and Uzbek, Eden’s innovative study explores the dynamics of Muslim life in this period. One of Stalin’s goals was to inculcate patriotism among Muslim communities, whose sense of belonging to Soviet society remained tenuous. The new permissiveness included reopening mosques and empowering those Muslim leaders who had survived the prewar purges, while keeping religious life under tight state control. Religious leaders endorsed by the state presented the fight against Hitler as a holy war, blending Islamic devotion with Soviet patriotism. At the same time, the religious resurgence that the state’s tolerance unleashed thwarted the government’s attempts to keep devotional life within desired limits. Eden demonstrates the close connections between the world of state-sanctioned “official” Islam and that of “unofficial” Islam. He points to the resilience of grassroots religious practices that survived the violent prewar campaign of atheism, among other factors, to explain the government’s failure to prevent the spread of unofficial Islamic activities. Moreover, officials entrusted with overseeing religious life often lacked a clear understanding of what the policy of “controlled permissiveness” entailed.