The book gathers a group of scholars interested in both public international law and EU law to cover different facets of the relationship between the European Union and customary international law. Considering the distinct perspectives taken by international law and EU law, while also looking into the space in between the two, individual chapters tackle complex questions such as whether and on what bases the European Union is bound by customary international law as a matter of international law and EU law; how the European Union contributes to the development of international custom; and how different stakeholders - the Court of Justice of the European Union, the EU's political organs and EU citizens - rely upon customary rules. The book thus offers a systematic account of the relevance of customary international law for the external relations and internal functioning of what is no doubt the most remarkable regional international organization of our time.

The book investigates how an analogy between States and international organizations has influenced and supported the development of the law that applies to intergovernmental institutions on the international plane. That is best illustrated by the work of the International Law Commission on the treaties and responsibility of international organizations, where the Commission for the most part extended to organizations rules that had been originally devised for States. Revisiting those codification projects while also looking into other areas, the book reflects on how techniques of legal reasoning can be - and have been - used by international institutions and the legal profession to tackle situations of uncertainty, and discusses the elusive position that international organizations occupy in the international legal system. By cutting across some foundational topics of the discipline, the book makes a substantive contribution to the literature on subjects and sources of international law.

The book investigates how an analogy between States and international organizations has influenced and supported the development of the law that applies to intergovernmental institutions on the international plane. That is best illustrated by the work of the International Law Commission on the treaties and responsibility of international organizations, where the Commission for the most part extended to organizations rules that had been originally devised for States. Revisiting those codification projects while also looking into other areas, the book reflects on how techniques of legal reasoning can be - and have been - used by international institutions and the legal profession to tackle situations of uncertainty, and discusses the elusive position that international organizations occupy in the international legal system. By cutting across some foundational topics of the discipline, the book makes a substantive contribution to the literature on subjects and sources of international law.