This book traces the history of Canadian think tanks and places them in a broader context to better understand the relationship between politics, the social sciences, and public policy analysis in North America. The efforts made by thinks tanks to influence public debate and harden political identities become apparent as social actors mobilize perspectives and organizational resources to impose their vision of social problems and the role of the state. Julien Landry presents a sociohistorical analysis of the emergence and evolution of Canadian think tanks that spans more than a century. He also draws on examples from the United States for this analysis and proposes a new synthesis of the literature on think tanks, social sciences, and public policy. In particular, he looks at the organization and rise of the social sciences, the strengthening of their technocratic functions, and their generalized use of language in analyzing public policy and intervening in social debate. This history of the relationship between the social sciences and public policy in Canada - drawing on examples from the United States - shows how the emergence and evolution of think tanks are tied to the ascension, consolidation, and generalization of expert discourse in public debates and policy development. This book fills an important gap in the history of Canadian think tanks by looking at them through the lens of sociopolitical developments that marked the twentieth century. Published in French.