Chapter 2 presents the current institutional framework, with a special focus on the exercise of the legislative function. After a brief presentation of the most relevant institutional principles, notably those of effectiveness, institutional balance, and sincere cooperation, the chapter turns to the Parliament, the Council, and the Commission and explains their prerogatives and internal structures in the light of the concept of “executive federalism.” The chapter shows that the legislative institutions of the EU, in line with the principles of autonomy and internal differentiation, allocate important preparatory tasks to different internal bodies (that is, parliamentary committees, Coreper, and GRI) and analyzes the role of those bodies in the adoption of legislation.