 In 1920 , Innis joined the department of political economy at the University of Toronto . He was assigned to teach courses in commerce , economic history and economic theory . He decided to focus his scholarly research on Canadian economic history , a hugely neglected subject , and he settled on the fur trade as his first area of study . <unk> had brought French and English traders to Canada , motivating them to travel west along the continent 's <unk> lake and river systems to the Pacific coast . Innis realized that he would not only need to search out archival documents to understand the history of the fur trade , but would also have to travel the country himself gathering masses of firsthand information and accumulating what he called " dirt " experience . 
