Entering 2025, the European Union (EU) finds itself at a pivotal moment, caught between internal demands for social cohesion and external forces of global competition, climate change, and geopolitical realignments. The EU relies on myriad institutions, bodies, and decentralized agencies to function. At the forefront are five key institutions, or “the Big 5”: the European Commission, the Council of the European Union, the European Parliament, the Court of Justice of the European Union, and the European Council. This technical note provides an overview of these institutions and the EU's legislative process. It examines the EU’s decision-making process (i.e., its efficiency), discusses fiscal federalism (i.e., task allocation at the governmental levels), and considers the EU’s democratic legitimacy in the context of principal-agent theory. The single market and the EU’s competitiveness are also discussed. The technical note ultimately asks students to consider what reforms may be necessary for the EU to reach its full potential.