This popular casebook exposes students to the most significant current legal issues relating to international organizations in a stimulating format, employing debates, simulations, and role-play exercises. The chapters cover international organizations related to peace and security, human rights, the environment, and the global economy, both within and outside of the UN system. The third edition updates all of the existing chapters, and adds new chapters addressing the role of international organizations in matters of humanitarian intervention, self-determination, and nuclear nonproliferation.