This volume offers a comprehensive analysis of the agency phenomenon in the European Union. It takes stock of the emergence and development of EU agencies, providing insight into the characteristics as well as the consequences of the ongoing EU agencification process. The volume traces the varied roots of and routes to agency emergence and institutionalization. It also analyses everyday decision-making processes within EU-level agencies, notably the management of such agencies, their role in the creation of network structures in European executive governance and in the implementation of EU legislation at the member state level, and the varied sources of agency accountability. The ambition of this volume is to offer an even-handed assessment and explanation of agency creation, design, and evolution at the EU level. The volume is targeted to academics, post-graduate students, and practitioners. Chapter authors include Deirdre Curtin, Renaud Dehousse, Morten Egeberg, and Thomas Gehring.