The world is getting smaller and increasingly interdependent every day. As a result, national and regional developments are, as a matter of necessity, seen in a global framework. States want to preserve their independence but they are confronted with a growing list of problems which they can only solve in cooperation with others. The sheer scale of the issues at stake calls for an institutional framework to give that cooperation a more permanent structure. Hence, decisions taken at the national level and results of intergovernmental cooperation have become closely intertwined. It is, therefore, appropriate in the framework of the International Encyclopaedia of Laws to make accessible comprehensive, substantial and readily available information on the most important IGOs, given their importance for the development of international law and intergovernmental co-operation at large. The fundamental changes taking place nowadays at an incredible pace within IGOs render it all the more necessary to put this information within easy reach. Some 50 leading organizations are described in separate monographs of approx. 100 pages each.