The Sources of International Law

The Sources of International Law

Second Edition

Hugh Thirlway

ISBN: 9780198841814 (Hardcover)
Publicado: 28 May 2019
Páginas: 272

ISBN: 9780198841821 (Paperback)
Publicado: 28 May 2019
Páginas: 272

This new edition of Hugh Thirlway’s authoritative text provides an introduction to one of the fundamental questions of the discipline: what is, and what is not, a source of international law. Traditionally, treaties between states and state practice were seen as the primary means with which to create international law. However, more recent developments have recognized customary international law, alongside international treaties and instruments, as a key foundation upon which international law is built. This book provides an insightful inquiry into all the recognized, or asserted, sources of international law.

It investigates the impact of ethical principles on the creation of international law; whether ‘soft law’ norms come into being through the same sources as binding international law; and whether jus cogens norms, and those involving rights and obligations erga omnes have a unique place in the creation of international legal norms. It studies the notion of ‘general principles of international law’ within international law’s sub-disciplines, and the evolving relationship between treaty-based law and customary international law. Re-examining the traditional model, it investigates the increasing role of international jurisprudence, and looks at the nature of international organisations and non-state actors as potential new sources of international law. This revised and updated book provides a perfect introduction to the law of sources, as well as innovative perspectives on new developments, making it essential reading for anyone studying or working in international law.


1. The Nature of International Law and the Concept of Sources
2. Treaties and Conventions as a Source of Law
3. Custom as a Source of International Law
4. General Principles of Law as a Source of Law
5. The Subsidiary Sources
6. Interaction or Hierarchy between Sources
7. Specialities: Jus Cogens, Obligations Erga Omnes, Soft Law
8. Subsystems of International Law
9. Some Alternative Approaches
10. Conclusion


Hugh Thirlway, Former Principal Legal Secretary, International Court of Justice, and Professor of International Law, Graduate Institute of International Studies, Geneva

Hugh Thirlway was Principal Legal Secretary to the International Court of Justice from 1989 to 1994, and has since been Professor of International Law at the Graduate Institute of International Studies, Geneva, Visiting Professor at Bristol University, and Visiting Professor at the University of Leiden.

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