The importance of the law of international organizations is continually increasing. This textbook, first published in German, explains and analyses not only the structures of international organizations in general, but also focuses on the interplay between the creation of institutional structures and important substantive areas of public international law. Thus, in the first and second parts of the book the general aspects of the law of international organizations are surveyed, whereas in the third part international security, human rights protection, trade, development and environmental protection are analyzed in terms of the interplay between substantive and institutional law. This third part is built on the assumption that the law of international organizations needs to be studied "in action", ie by looking at highly institutionalized areas of international law as a way of analyzing the mutual influences between institutional and substantive international law. In fact all important parts of international law are today institutionalized in different international organizations, a phenomenon which is reflected in the title.

Up to now, there has been no other book on international law which brings together institutional and substantive aspects in a comparable manner. This text book is aimed at students of the law of international organizations but also to students in the social sciences, above all, political science. It will also be useful to practitioners in the field of international institutions.