This Companion offers a global, comparative history of the interplay between religion and war from ancient times to the present. Moving beyond sensationalist theories that seek to explain why 'religion causes war,' the volume takes a thoughtful look at the connection between religion and war through a variety of lenses - historical, literary, and sociological-as well as the particular features of religious war. The twenty-three carefully nuanced and historically grounded chapters comprehensively examine the religious foundations for war, classical just war doctrines, sociological accounts of religious nationalism, and featured conflicts that illustrate interdisciplinary expressions of the intertwining of religion and war. Written by a distinguished, international team of scholars, whose essays were specially commissioned for this volume, The Cambridge Companion to Religion and War will be an indispensable resource for students and scholars of the history and sociology of religion and war, as well as other disciplines.