The introduction offers a wide-reaching conceptual overview of Making Sense of the Great War’s approach to morale, as well as outlining its structure. It foregrounds the monograph’s key concepts and contributions. It defines morale in both its historical and historiographical context, before offering this monograph’s conceptualisation of the phenomenon as a process as well as an end state. It argues that to understand morale, one must study how combatants either positively or negatively rationalised their role as soldiers and constructive members of the military. The monograph’s methodology and source material are also described – with a particular focus on its interdisciplinarity and use of a large swathe of contemporary ego-documents. The definitions of chronic and acute crisis are discussed alongside descriptions of the scholarly debates revolving around the three major ‘crisis periods’ the book covers. The introduction explains the book’s focus on the ways in which the physical environment, social groups, and individual psychologies interacted as men made sense of war.