European legislation affects countless aspects of daily life in modern Europe but just how does the European Union make such significant legislative decisions? How important are the formal decision-making procedures in defining decision outcomes and how important is the bargaining that takes place among the actors involved? Using a combination of detailed evidence and theoretical rigour, this volume addresses these questions and others that are central to understanding how the EU works in practice. It focuses on the practice of day-to-day decision-making in Brussels and the interactions that take place among the Member States in the Council and among the Commission, the Council and the European Parliament. A unique data set of actual Commission proposals are examined against which the authors develop, apply and test a range of explanatory models of decision-making, exemplifying how to study decision-making in other political systems using advanced theoretical tools and appropriate research design.