This volume deals with expulsion from and suspension of membership rights in international organizations. This is an area of the law of international organizations which has attracted limited attention by academic writers. The book examines some 35 different international organizations by analyzing the relevant provisions in their constitutive instruments and, where available, discussing the practice. Additionally, it describes in considerable detail the practice of rejecting delegations' credentials as a means of excluding Member States from participation. Moreover, it suggests solutions for those international organizations lacking expulsion and/or suspension clauses by applying the Vienna Convention on the Law of Treaties and the theory of countermeasures in international law, especially as codified by the International Law Commission. Finally, the book offers a model expulsion and suspension clause to be incorporated in existing or future international organizations.