The dissertation identifies the origins of the present disparity of health conditions between Indian communities and mainstream society in western Canada. It examines the relationship between economics and health of Indian populations in the Canadian northwest from the early eighteenth century to the end of the nineteenth century. It documents the development of the fur trade in relation to changes in the geographical distribution of aboriginal societies resulting from the differential impact of introduced European diseases. For a period of one hundred and fifty years, infections that came as a consequence of trade were the primary source of mortality due to illness among First Nations. In addition, social pathologies resulting from European trade strategies affected the well being of communities in the northwest. Climate and environment contributed to the differential success of many groups integrated into the global economy through the fur trade. Canada's acquisition of the northwest changed this pattern. Its commitment to the terms of Treaties opened the west for agricultural development and settlement. The Dominion's development strategy, the National Policy, coincided with the extinction of the bison, undermining the ability of plains Indians to compel the government to deliver on their Treaty commitments. To facilitate the implementation of its economic and political order, the Dominion used its famine relief strategy as a means to subjugate them. By the early 1880s, tuberculosis emerged as a full blown epidemic among the Indians of the plains. The spread of tuberculosis through the Indian population of the plains was the result of the protracted period of malnutrition. Punitive measures imposed after the brief armed resistance to Dominion hegemony further weakened the population already largely infected with the disease. Severe mortality resulted from the spread of acute infectious disease among the compromised population. Within fifteen years of signing Treaties many plains populations declined to their demographic nadir.