This article examines Talbot Mercer Papineau's letter to Henri Bourassa and Papineau's impact on Canadian cultural mobilization and its war culture. European historians of the First World War have used the concept of cultural mobilization to understand the lines that connected battlefront and home front and their impact. As evidenced by the recent historiographical review of First World War literature in the pages of the Canadian Historical Review, Canadian scholars ought to adopt a similar framework to unite two literatures that separately focus on the military history and social history of the war. Papineau's 1916 letter provides a glimpse into how a soldier expressed his perspective of the war from the frontlines and participated in the mobilization of Canada's war culture. His writing was a result of his war experience, but Papineau wrote it for a Canadian audience at home, and its wide publication exposed his views to millions across Canada and Britain. Papineau urged Canadian citizens (specifically French Canadians) to support the purpose and value of the war as understood by Canadian soldiers. This article offers Papineau as a case study to encourage a new direction for the Canadian history of the First World War and further work on cultural mobilization and war culture.