Given the interest in Islam's growing significance in Central Asia, Russia, and the Caucasus, this massive and meticulous history of Islam in the Soviet Union's postwar decades provides indispensable background. Notwithstanding the Soviet state's animus, Islam persisted in officially acknowledged mosques and clergy as well as among unregistered, illegal associations and mullahs. Using the archives of the Communist regime's religious watchdog agency, Ro'i relates in detail how official and unofficial Islam fared, particularly in the critical years of 1943 to 1964. He attributes Islam's survival to its central place in social life, the efforts of unregistered clergy members, and, ironically, the desultory way in which the regime went about extirpating it. Completing the irony, Mikhail Gorbachev sparked a resurgence of Islam, which the current leaderships in Central Asia and the Caucasus try to control much like Gorbachev's predecessors did.