This report provides a comprehensive analysis of key aspects of European Union law. It begins by examining the powers of the European Commission, detailing its role in legislative initiatives, budget proposals, and its interactions with non-member countries. The report explores the Commission's power of opinion and recommendation, particularly in the context of the Economic and Monetary Union, and its monitoring and implementing powers conferred by treaties and delegated by the Parliament and the Council. The report then transitions to an in-depth discussion of the law on preliminary references under Article 267 of the Treaty on the Functioning of the European Union (TFEU), explaining the procedure that enables national courts to seek preliminary rulings from the European Court of Justice (ECJ) and its role in interpreting EU law. It distinguishes between discretionary and mandatory reference procedures and outlines the grounds on which the ECJ may declare a preliminary reference inadmissible. The report concludes by summarizing the key findings regarding the Commission's legislative powers and the preliminary reference procedure, emphasizing their importance in the EU legal framework.