Synopsis The present volume contains analyses written during the period 2001-2002, dealing with the evolving concept of universal jurisdiction, with doctrinal aspects of international humanitarian law, and with the challenges faced by legal theory in addressing issues of international terrorism. The author’s guideline has always been that measures of international law enforcement-whether in regard to states or individuals-have to be consistent with the norms governing peaceful co-existence in general and with the United Nations’ rules and procedures of collective security in particular. T his book does not aspire to provide a compendium of the history and actual practice of international criminal law, or of the present state of international humanitarian law. Instead, one of the author’s main intentions is to reflect upon the legal and philosophical foundations of universal jurisdiction and to demonstrate, in exemplary cases, the problems of legitimacy faced by international legal institutions in the actual context of power politics. The body of norms of international criminal law and that of international humanitarian law war analyzed here with regard to the United Nations Organization’s efforts towards a universal-and consistent-set of rules governing international relations. The present volume is the result of years of involvement with issues of conflict resolution and international law in the framework of the research projects and conferences of the International Progress Organization, a non-governmental organization in consultative status with the United Nations. The book is therefore dedicated to the International Progress Organization in Commemoration of the thirtieth anniversary of its foundation in 1972.the the book further undertakes a critical evaluation of the doctrine of humanitarian intervention and deals with the challenges posed by terrorism to the international rule of law.