Includes bibliographical references and index.

I. The nature of international law and the concept of sources -- Introduction -- Formal and material sources -- Enumeration of the recognized formal sources -- Nature and operation of the sources -- Whose law? States and non-State actors -- Are there additional sources, not in Article 38? ; Unilateral acts 20 ; Decisions of international organizations ; Agreements between States and international enterprises ; Other proposals -- Religious law as a rival or additional source -- Is the theory of sources still sufficient? -- II. Treaties and conventions as a source of law -- Pacta sunt servanda -- The limits of treaty-law : jus cogens and the relative effect of treaties -- Commitment to the treaty-obligations -- Unilateral acts as inchoate treaties? -- III. Custom as a source of law -- Introduction -- Constituent elements of custom ; Introduction ; State practice ; The opinio juris ; The role of General Assembly resolutions -- Changes in customary law -- The relevance of ethical principles to customary law -- The 'persistent objector' -- General and local customary law -- IV. General principles of law as a source of law -- What are the 'general principles of law'? -- The role of equity -- General principles of law and non liquet -- V. The subsidiary sources -- Introduction -- Judicial decisions ; International tribunals ; Municipal courts -- The teachings of publicists -- VI. Interaction or hierarchy between sources -- Simultaneous and identical obligations under treaty and under customary law -- The 'hierarchy of sources' -- VII. Specialities : jus cogens, obligations erga omnes, soft law -- Superior norms and their sources : jus cogens and obligations erga omnes ; The source or sources of obligations erga omnes ; The source or sources of norms of jus cogens -- Soft law -- VIII. Subsystems of international law -- 'Self-contained regimes' and their limits -- Human rights law ; Human rights law under treaty and as custom ; Human rights as deriving from general principles ; Human rights and Islam -- Humanitarian law ; Treaties and conventions ; Customary law or an independent source of law? -- WTO, ICSID : trade and investment law dispute settlement -- International environmental issues -- International criminal law -- IX. Alternative approaches -- Alternatives to the traditional doctrine of sources as a whole ; Rational choice theory : Andrew T. Guzman ; Jean d'Aspremont : Formalism and the sources of international law ; Matthias Goldmann : standard instruments for the exercise of international public authority -- New approaches to customary law ; 'A new theory with practical applications' : Brian D. Lepard ; Reconciliation of 'traditional' and 'modern' approaches : Anthea Roberts -- X. Some concluding reflections.