'This book adds something original and enriching to EU law: a new perspective on direct effect which is both persuasive and disruptive. Its core argument deserves to become part of the canon of the field, something that every scholar and teacher of the law must integrate into their thinking if they wish to understand why direct effect exists and what it means for the European Union. Phelan's explanation of how direct effect made possible the ending of inter-state retaliation, and thereby the construction of supranational integration as we now know it, is based on careful analysis of a series of key judgments and the judges who wrote them. The story he tells shines a light on direct effect which is every bit as illuminating as the stories about individual rights and effectiveness upon which lawyers have relied until now.' Gareth Davies, Vrije Universiteit Amsterdam