In the winter of 1918-1919, a pandemic of influenza crossed the globe, killing as many as 50 million people. This dissertation is a local study of influenza in Winnipeg, Canada. It dissects the social responses to the disease from four different perspectives: that of the public health and medical authorities; middle class Anglo-Canadian women volunteers who provided nursing care and material relief to the city's poorer influenza victims; working class and immigrant families; and organized labour. The dissertation argues that the influenza epidemic, coming on the heels of the devastating Great War, and arriving in the midst of class, ethnic, and gender conflicts, played a role in deepening the social cleavages of Winnipeg society in the period, particularly those of class and ethnicity. Class and ethnic tension was not the inevitable outcome of the epidemic. Rather, it was the result of the social inequality of the disease's impact--working families represented a disproportionately high number of influenza's victims--and the failure of public authorities to mount a compassionate and cooperative community effort to fight the disease. The volunteerism of middle class Anglo-Canadian women, too, failed to build the bonds of community. Labour believed that the state response to influenza was a betrayal of principles of justice and public good. Workers' families bore the brunt of public closures and layoffs. A spirit of mutualism sustained families and neighbourhoods through the disease, and contributed to the mobilizing successes of the workers' movement in 1918-1919. The trauma of the epidemic suggested the fragility of the social order, and workers' capacity to build an alternative society. Their vision of social transformation included the creation of the "springs of health": a living wage, quality housing, and equal access to a democratic medical system. Many working families, nevertheless, found it difficult to recover from the loss of spouses and children. Their stories suggest that influenza had a long-term impact upon the evolution of post-war Canada that we are only just beginning to understand.