This book assesses the influence of the European Court of Justice (ECJ) on the governance of the EU and concentrates on the following themes: the function of the ECJ as the Supreme Court of the Union; judicial independence; the protection of the individual in the EU legal order; the relationship between the ECJ and the other branches of government at national and Union level; and the relationship between the ECJ and the Court of First Instance, the European Court of Human Rights, and national courts. It assesses the impact of the EU Constitution on judicial protection and covers, among other topics, Union competence, direct effect, preliminary references, locus standi for individuals, a statistical analysis of judicial review, and judicial activism. It combines a close analysis of the case law with a wider contextual law approach.