Menahem Mendel Schneerson (1902-1994) was the seventh and seemingly last Rebbe of the Habad-Lubavitch dynasty. Marked by conflicting tendencies, Schneerson was a radical messianic visionary who promoted a conservative political agenda, a reclusive contemplative who built a hasidic sect into an international movement, and a man dedicated to the exposition of mysteries who nevertheless harbored many secrets. Schneerson astutely masked views that might be deemed heterodox by the canons of orthodoxy while engineering a fundamentalist ideology that could subvert traditional gender hierarchy, the...