Here is a great book review at The Christian Century on the book The Great and Holy War: How World War I Became a Religious Crusade.
Philip Jenkins builds upon this specialized historiography as it treats the Great War as a global religious conflict. His vividly written synthesis beĀlongs at the top of reading lists on the conflict.
Not only does Jenkins provide detailed accounts of interactions between religion and militarism, religion and combat, and religion and trauma on all sides of the war, he also demonstrates that the world torn apart by the Great War was a world of many shared religious concerns and vocabularies, a world that needed the extreme fission that religion accomplishes in order to launch and sustain such a brutal conflict.