The impact, and indeed long term survival of the European Community depends to a great extent on the effective practical implementation of Community law. This book compares the role of the Commission and national administrations in supervising and enforcing EC law, paying attention to what powers have been granted and what constraints exist, and when the Commission and national administrations are treated differently, and if that difference is justified. The main object of the book is to analyse the main tools for supervision, such as inspections, and the main infringement procedures. Issues such as deadlines to act, discretion, the capacity of Administrations to cope with their responsibilities in this area, and the problem of administrative coordination, are examined. The author also offers an overview of the system of EC administrative law procedures, which have evolved to prosecute infringements committed by Member States. The author analyses the reasons lying behind the creation of those procedures, and the interaction between them, and focuses on the importance of Article 169.The book relies primarily on an analysis of legislation, case-law and the most relevant legal rules, but also draws on the literature in political science and public management. This analysis is supplemented by the results of questionnaires and interviews with both national and Commission officials comparing their different views.