This book offers a rigorous empirical and theoretical analysis of an important dimension of European integration - the implementation of EU legislation and its effect in the wake of the accession of ten new member states to the EU in 2004. The authors concentrate on the key field of social policy, which is of vital interest for the viability of the welfare state and the future of labour law standards in Europe. The authors offer in-depth empirical case studies of three of the most significant pieces of EU social legislation: the Working Time Directive, the Equal Treatment Directive and the Employment Equality Directive. Their analysis makes it possible for the authors to make useful generalizations for the policy field as a whole.