From the first Jewish revolt against Rome in the first century CE to contemporary Islamic fanaticism, faith in the hands of religious zealots has been a powerful and often catastrophic means of enacting radical change. Ultimate Devotion examines a range of religious movements across history to reveal the striking similarities in the way they emerged, the characters of their leaders and followers, and their often tragic conclusions. A rich variety of archaeological materials intersect with textual evidence and anthropological theory to develop a model of mass action inspired by intense religion. In its exploration of religious rebellion in history, Ultimate Devotion illuminates religious fanaticism today.