As 2014 marked the centennial of the outbreak of the First World War, this volume explores the powerful religious dimensions of this dreadful event. The war was fought by the world’s leading Christian nations, and on all sides, clergy and Christian leaders offered a steady stream of patriotic and militaristic rhetoric. Many spoke the language of crusade, of apocalypse and Armageddon. Not in medieval or Reformation times, but in the age of aircraft and machine guns, the majority of the world’s Christians were engaged in a religiously defined struggle that claimed the lives of more than ten million soldiers and sailors and of millions of civilians. Later generations find that passionate religious commitment deeply troubling and in need of urgent explanation.