The Introduction begins by examining the treatment of First World War theatre in academic scholarship over the last century, and identifies reasons for its neglect and the resurgence of interest in the topic over the last decade. It considers this resurgence in relation to work on popular theatre, the focus on cultural histories of the war, and the centrality of theatre and performance to centenary commemorations. In addressing how theatre contributed to the war effort it considers themes including: recruitment and enlistment, fundraising for war charities, and the value of theatre for servicemen and the wouded. It also considers challenges to theatre production created by the wartime conditions. Drawing on the work of the Great War Theatre project it highlights the large number of war-themed plays produced during the war, arguing that plays did not have to ignore the war to be entertaining or popular. The introduction emphasises the importance of looking at the diversity of theatrical production across the country and in both amateur and professional contexts. As such it provides the framework for the in-depth analyses of these and other topics examined across the volume.