Whereas uncertainty and distrust have been key variables in explaining the lack of cooperation and the persistence of conflict in international politics, the role of trust has largely been neglected. In this study, Christoph Elhardt develops a working notion of trust in International Relations (IR) theory. Building on a variety of approaches from sociology and social philosophy, he demonstrates how a more nuanced understanding of trust allows us to understand how uncertainty is managed in the everyday practices of international politics. His theoretical account of trust attempts to answer the following questions: How can trust be conceptualized? How can we explain the emergence of trust in international politics? Under what conditions is trust likely to emerge? Why do actors take trustworthiness for granted in some situations and not in others? The Bourdieusian notion of trust developed throughout Trust and Cooperation in International Relations Theory challenges particularly those arguments in IR theory which question the possibility of continuous interstate cooperation due to the uncertainty about states’ intentions and motivations.This study has been awarded the 2010 Young Talent Award for outstanding diploma or master‘s theses in political science by The Austrian Political Science Association (ÖGPW).