The Oxford Handbook on the Sources of International Law is the very first comprehensive work of its kind devoted to the question of the sources of international law. It provides an accessible and systematic overview of the key issues and debates around the sources of international law. It also offers an authoritative theoretical guide for anyone studying or working within but also outside international law wishing to understand one of its most foundational questions. This Handbook features original essays by leading international law scholars and theorists from a range of traditions, nationalities and perspectives, reflecting the richness and diversity of scholarship in this area.