For over half a millennium global law has been central to the practice and analysis of international relations. How has the use of global law shaped international relations of the past and present and how will it shape the future? This work assembles the key articles that have defined the scholarly field of global law to explore customs, treaties and international institutions, the roles they have played in international relations and the effect they have had and will continue to have in the international system. With a wide range of articles covering the classic debates of the role of global law, as well as introducing case studies of the applications of global law, it allows one to ask what the future of global law will be.