American troops sent to Northern Ireland in 1942 were warned against discussing religion and politics with their hosts. Historical writing on wartime Northern Ireland appears to have partially heeded that advice by focusing on politics to the near-exclusion of religion. This book, the first detailed exploration of religion in wartime Northern Ireland, examines how churches responded to the challenges of international conflict. It presents an analysis of mid-twentieth century Northern Ireland that attends to the complexity of religion which has more commonly been portrayed in binary and crudely homogeneous terms.