Do independent boards of appeal set up in some EU agencies and the European Ombudsman compensate for the EU Courts' shortcomings? The judicial review of complex legal acts is often not sufficiently thorough. It remains inaccessible to many private parties such as NGOs. The boards of appeal should be able to inquire into the uncertain science and intricate technicalities. The Ombudsman should open the possibility of redress and public accountability beyond courts. This book examines the current 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 diverse but complementary ways in which the examined 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.