This textbook introduces readers to international law by linking it to the Harry Potter universe. Given the current changes in the international sphere away from a state-centric system to a multitude of non-state actors, it tests the legal regime by applying it to the out-of-the-box concept of wizards and thus rids the doctrinal debate of political factors. More specifically, the book explains core concepts of public international law, covering the elements of a state, state responsibility, jurisdiction, enforcement of international law and immunity. In the wizarding world, it addresses questions of statehood by discussing when a wizarding state is responsible for the crimes committed by its wizards, who has jurisdiction over crimes, and how international law is enforced. In addition, it introduces and explains the fundamentals of international humanitarian law, international human rights law, international criminal law, and air law by applying them to the wizarding world. The textbook is intended for anyone looking for an accessible introduction to public international law and its application.