Professor Martti Koskenniemi is Emeritus Professor of International Law at the University of Helsinki and Director of the Erik Castrén Institute of International Law and Human Rights at the University of Helsinki. He argued in his book, ‘The Gentle Civilizer of Nations’ (2001) that modern international law arose in the last third of the 19th century. Its ideological centre lay in the concept of ‘civilization’ that has later on been equated simply with modern statehood. However, by mid-19th century, another view to think about law, politics in the international world was developing in Europe that focused on the concept of ‘society’. This had its British and French versions as well as, in particular, turn-of-the century German Staatslehre (doctrine of state and law). As ‘society’ was captured in other emerging disciplines – sociology and political economy in particular – only a rather formalist notion of it remained with law. Nevertheless, throughout the 20th century, challenges to a state-centric international order law have been framed as the search for a ‘law of an international society’. Professor Koskenniemi will review some of these efforts and end up with some reflections about the significance and variants of social thought in present-day ideas about legal pluralism and ‘transnational law’.