Here in one volume is the essential Leo Gross: all the important essays of one of the twentieth century's keenest and most influential legal thinkers. Gross was the pre-eminent formulator of 'modern positivism', refining the approach to public international law, but taking it further and modifying it to fit the realities of the post-World War II international environment. This volume, a tribute to his intellectual stature as well as a broad and representative selection of his work, provides the next generation of students of public international law and organisation with a tool for understanding the future of international relations. Full of insight and learning, these essays also serve as a reminder to jurists of how much impact one good mind can have on the course of affairs.