This book project deals with the procedural law of the Court of Justice of the European Union (CJEU), i.e. the rules, laid down in the Court’s Statute, Rules of Procedure and internal practice, that organize the concretization of substantive law. The CJEU is today the most powerful court beyond the state and a central actor of European governance. While the query to understand its authority and legitimacy has kept generations of EU scholars busy the role of procedural law in the construction of this authority and its legitimation has not been systematically engaged in. Quite to the contrary, standard accounts on the CJEU’s procedural law portray it as a technical discipline concerned with the effective working of the judicial machinery.