(Series Information) European Papers - A Journal on Law and Integration, 2021 6(2), 891-901 | Article | (Table of Contents) I. Introduction. - II. Case 149/79 Commission v Belgium. - III. The context/case dialectic. - IV. Findings on legal reasoning to strengthen doctrinal research. - V. Procedural practice. - VI. Insight into actors and institutions. - VII. Concluding remarks. | (Abstract) In its final decision of 26 May 1982, the Court of Justice established which of two competing interpretations of the public service exception in art. 48(4) of the EEC Treaty (currently art. 45 TFEU) would define the ambit of free movement of workers to this day. Out of nine Member States, four were actively involved in the proceedings, showing the controversy and importance surrounding the implementation of free movement in the public service of domestic legal orders in this early stage of European integration. Findings from an analysis of the dossier for Commission v Belgium were gathered in reports drafted as part of a fascinating project on the "Court of Justice in the Archives". This Article showcases the interconnectedness of actors, institutions and procedure that emerges from the dossier. The legal reasoning underpinning the case is re-evaluated on the basis of submissions and the evidence contained in the dossier. The illustrations selected for this Article demonstrate how the dossier can be deployed as a new instrument to further socio-legal and legal research on the jurisprudence and practice of the European Community.