"This edited volume finds its origin in a conference on the theory and practice of customary international law (CIL) and its interpretation, held in May 2019 at the University of Groningen. The conference was co-organized by the TRICI-Law project and the Interest Group on International Legal Theory and Philosophy (IGILTP)."--ECIP Preface.

Between pragmatism and disenchantments : the theory of customary international law after the ILC Project / Jörg Kammerhofer -- The custom-making moment in customary international law / Jean d'Aspremont -- Misinterpreting customary international law : corrupt pedigree or self-fulfilling prophecy? / Noora Arajärvi -- The logic of absence in customary international law : an open-system approach / Anna Irene Baka -- Schrödinger's custom : implications of identification on the interpretation of customary international law / Markus P. Beham -- The significance of state consent for the legitimate authority of customary international law / Andreas Føllesdal -- Custom and the regulation of 'the sources of international law' / Diego Mejía-Lemos -- The ILC's new way of codifying international law, the motives behind it, and the interpretive approach best suited to it / Luigi Crema -- Beyond formalism : reviving the legacy of sir henry Maine for customary international law / Andreas Hadjigeorgiou -- Enkapsis and the development of customary international law : an encyclopedic approach to inter-legality / Romel Regalado Bagares -- Customary international law in the reasoning of international courts and tribunals / Vladyslav Lanovoy -- Eureka! On courts' discretion in 'ascertaining' rules of customary international law / Letizia Lo Giacco