Do independent boards of appeal set up in some EU agencies and the European Ombudsman compensate for the shortcomings of EU Courts? This book examines the operation of EU judicial and extra-judicial review mechanisms. It confronts the formal legal rules with evolving practices, relying on rich statistical data and internal documents. It covers detailed institutional arrangements, the standard of review, the types of cases and litigants, and the activity of the parties in the process. It makes visible the diverse but complementary ways in which the mechanisms enhance the authority of EU legal acts and processes. It also reveals that scarce resources and imprecise rules restrict the scope of review and hinder independent empirical investigations. Finally, it casts light on how a differentiated system of judicial and extra-judicial review can accommodate various kinds of technical and political discretion exercised by EU institutions and bodies.