Secrecy is a prevalent feature of politics within and among liberal democratic states, as well as in the relations between states and international organisations. However, surprisingly little research in political science has explored the effects of secrecy on policy making; the evolution of the regulatory frameworks that govern the use of secrecy; and the tensions between secrecy and transparency.This fascinating volume examines secrecy in European politics across a range of EU and national settings and policy domains, exploring the technological, social and political developments which appear to signal the end of privacy and the rapid expansion of political secrecy in European multi-level settings. Consequently, the tensions between democratic accountability with its transparency requirements, and political secrecy, which is typically justified on grounds of effectiveness of state action, have become more marked and more politicised. Engaging with these developments, the authors focus on actors’ motivations in secret politics; institutional perspectives that highlight contestation over secrecy norms; and organisational perspectives that emphasise the diversity of secrecy cultures.This book will be of great interest to students, researchers and professionals of political science and law. It was originally published as a special issue of the journal West European Politics.