This paper is a revised and updated (till 1 December 2016) version of Professor Jurian Langer's inaugural lecture held on 31 March 2015. The paper focuses on the preliminary ruling procedure of Article 267 of the Treaty on the Functioning of the European Union. This procedure gives every national court the power – and even imposes an obligation on some courts – to refer preliminary questions concerning the interpretation of European law and the validity of the acts of EU institutions to the Court of Justice of the European Union. This procedure is a vital and successful dialogue between national courts and the Court of Justice – one beset by old problems and facing new challenges. The author looks in this paper more closely at the preliminary ruling procedure and its functioning. What factors affect the success of this dialogue? And how can we ensure that it continues to be successful? More specifically, Professor Jurian Langer examines the opportunities for national courts and the Court of Justice – within the current parameters of the European treaties – to influence the dialogue and to continue successful cooperation. The author argues that if the main actors involved continue to shoulder their shared responsibility underlying the procedure, it will continue to be a success. In this context, the paper suggests, among other things, an increased 'European' role for the highest national courts by relaxing the CILFIT-criteria, an increased use of Article 101 of the Rules of Procedure as well as a stricter admissibility rule regarding references in relation to internal situations.