A comprehensive treatment of the law of treaties written from the point of view of a practitioner of 35 years experience: the first book of its kind. Aust provides a wealth of examples of the real problems experienced in making and using treaties day by day, not just when a treaty is the subject of a court case. As such it is invaluable to the practitioner. Aust aims to supply the reader with a full and rounded understanding of all aspects of treaties. He avoids technical language as far as possible, making his work, there is plenty to interest and inform law students and teachers (it has established itself as a course book), as well as those specialising in political science, international relations or diplomacy.