Many historians have downplayed the significance of interwar internationalism, treating the League of Nations and the efforts of internationalists as idealistic failures in an age that was characterised by international tensions and aggressive nationalisms. 'Internationalism Reconfigured' challenges such narratives by assessing transnational projects that were launched or transformed after World War One. In the face of national antagonisms, it proved challenging to re-establish international norms or organisations. Yet the League of Nations offered a new framework for activists, experts and policymakers. Consequently, and in spite of the legacy of war and the emergence of new conflicts, the years between 1919 and 1939 saw a great variety of transnational endeavours, shaped by a belief in the feasibility of a new global order. The chapters in this book offer an in-depth discussion of specific transnational movements and organisations. They explore how the League of Nations system engaged with governments or non-state actors, and shed light on the contrasting rationales for transnational cooperation. As a whole, the volume highlights both the extent and the boundaries of interwar internationalism. It also reveals the contrasting motivations that informed internationalist action. With fresh research from several European countries, the book makes an original contribution to the transnational history of the interwar years.