The modernist historiographical model of the Great War neglects such traditional modes of thought as religious response to battle. Drawing on the testimony of over 500 British and American soldiers, Schweitzer provides an in-depth account of topics such as soldiers' prayers and biblical readings, as well as religious doubts. As a detailed snapshot of religion during the war, this study provides a crucial preamble to studies of the legacy of the Great War. The lack of a satisfactory scholarly study has left interpretation of the role that religion played in soldiers' lives to the pronouncements of their contemporaries who often either viewed World War I as an opportunity to spark a religious revival or as an event that crushed religious faith. Schweitzer argues that neither of these interpretations is accurate, and he hopes to replace them with a model that arranges responses on a spectrum ranging from absolute faith in God to atheism. Based on extensive archival research, this study establishes a detailed model of the spiritual lives of British and American soldiers during the war. After sketching this spiritual history, he concludes that both British and American soldiers were more religious than previous writings have indicated.