This book seeks to re-appreciate the concept of customary international law as a form of spontaneous societal self-organisation, and to develop the methodological consequences that ensue from this conception for the practice of its application. In pursuing this aim, the author draws from three different strands of scholarship that have not yet been considered in connection with one another: First, general jurisprudential theories of customary law; second, theories of customary international law, especially as they relate to international relations scholarship; and third, methodological approaches to the interpretation of international law. This expansive, philosophical layout of the book enables the author to put the conceptual enigmas of customary international law into a broader perspective. Among the issues discussed in the book are the dichotomy of its traditional and modern forms and the respective benefits and disadvantages of inductive and deductive approaches to its ascertainment. In the course of this analysis, the author draws insights from Friedrich August Hayek’s theory of law as a ‘spontaneous order’, an information-processing device which enables the participants of a legal system to make use of decentralised knowledge. The book argues that the major advantage of custom as a source of international law lies in the fact that it is the result of a gradual process of trial and error, rather than the product of deliberate planning. This makes it a particularly apposite source of law in a time of seismic shifts in the distribution of power within a vastly diverse community of States, when a new global order is expected to emerge, the contours of which are not yet clearly discernible. This book applies general concepts of legal philosophy to explain the continuing relevance of custom as a source of international law while at the same time inferring from this theoretical framework concrete practical and methodological consequences, the most important of which is the special role that purposive interpretation plays with respect to rules of international custom. Given this broad approach, the book will be of interest to several groups of potential readers including academics interested in the philosophy of customary law in general, academic international lawyers and legal practitioners, especially judges, scholars of international relations and all those interested in how the international community of States organises itself.

States often regard themselves bound by treaty rules which have developed under customary international law, even though many of the treaties themselves have not been ratified. The Law of the Sea Convention, for instance, has generated new customary rules which modified the 1958 Geneva Conventions. These & many other issues are dealt with clearly & systematically in this informative handbook on the relations between written & unwritten international law. The conclusions of the first edition of Customary International Law & Treaties were largely confirmed by the International Court of Justice in the Nicaragua Case. This fully revised second edition, while basing itself on the original version, brings the subject up to date.

Provides an in-depth study of the theory, history, practice, and interpretation of customary international law.

This book sets out to articulate a comprehensive theory of customary international law that can effectively resolve the conceptual and practical enigmas surrounding it. It takes a multidisciplinary approach and draws insights from international law, legal theory, political science, and game theory. It is anchored in a sophisticated ethical framework and explores the interrelationships between customary international law and ethics.

A collection of essays on the various aspects of the legal sources of international law, including theories of the origin of international law, explanation of its binding force, normative hierarchies and the relation of international law and politics.

Fundamentals of Public International Law, by Giovanni Distefano, provides an overview of public international law’s main principles and fundamental institutions.

Because of its unique nature, the sources of international law are not always easy to identify and interpret. This book provides an ideal introduction to these sources for anyone needing to better understand where international law comes from. As well as looking at treaties and custom, the book will look at more modern and controversial sources.