Wars are increasingly studied as periods of intense transnational exchanges. Against this background international organisations have developed into particularly relevant fields of research: They represented and at the same time established many of these interrelations. Looking at international organisations as dynamic and complex platforms facilitating social, economic and cultural exchanges, the articles of this issue concentrate on the question how they functioned and how they influenced the war by providing human and technical resources to national governments. Taken together the articles offer a fresh look at the Second World War as well as on international organizations which cannot be reduced to intergovernmental bodies only fulfilling diplomatic missions. The articles also emphasize the role that international organisations played in keeping alive liberal international networks and values as well as maintaining and strengthening – though not without multiple tensions – the transatlantic hegemony over the world in the aftermath of the Second World War.