The utility of traditions to intellectual historians has been questioned in recent years by scholars who believe that the use of the concept can lead to anachronism or worse. This article argues that traditions play a crucial explanatory role for historians of international thought and must play a part in explanations of what thinkers believed and how their thought evolved. It begins by reviewing the literature on the revival of intellectual history in International Relations and the emergence of new interpretations of past international thought. It then puts the case for the concepts of tradition and dilemma in the history of ideas and in the history of British international thought in particular. It concludes by introducing the articles in this special issue.