What does EU law truly mean for the member states? This book presents the first encompassing and in-depth empirical study of the effects of ''voluntaristic'' and (partly) ''soft'' EU policies in all 15 member states. It examines 90 case studies across a range of EU Directives and clarifies contemporary issues in political science, integration theory, and social policy. The study concludes that major implementation failures prevail and that, to date, the European Commission has not been able to adequately perform its control function.