International law is constantly evolving, but we have a very limited understanding of how it evolves. Lawyers tend to point to the formal doctrine of sources without taking into account the informal, social life of legal norms. International relations scholars usually focus on treaty-making and ignore the other, less easily understood forms in which the international legal order develops. In this seminar, we seek to gain a better idea of the processes and conditions of international legal change. We will look at the urgency with which the problem of change was approached by thinkers at different points in time, but we will aim in particular at a clearer analysis of the empirical phenomenon of change. We will use different issue areas of international law to discern commonalities and differences between them, and we will pay attention to particular actors and factors behind international legal change, among them powerful states, norm entrepreneurs, courts, and expert bodies. The course requires a written research paper on a topic to be determined by the student in cooperation with the instructor. Students will present a draft of the paper at a workshop session towards the end of the course.