This book analyzes the law-creating process relating to the interpretation of constituent instruments of international organizations. This topic is one of the key issues concerning the structures and activities of international organizations. It differs from other books in the field by suggesting that, under the influences of the inherent dynamism of international organizations, the interpretative framework of their constituent instruments is not the same as that of ordinary treaties. It also concludes that the interpretation of the constituent instruments of international organizations deviates from the interpretative framework regulated by the law of treaties as codified by the Vienna Convention on the Law of Treaties. The book will be of prime interest to academics in the fields of international law and international organization and treaty law.