The European Commission is at the centre of the EU political system. Within its five-year terms each Commission proposes up to 2000 binding legal acts and therefore crucially shapes the form and substance of EU policy, which in turn impacts on the daily lives of more than 500 million Europeancitizens. However, despite the EU Commission's key role in setting the agenda for European decision making, little is known about its internal dynamics when preparing legislation. This book provides a problem-driven, theoretically-founded, and empirically-rich treatment of the so far still understudied process of position-formation inside the EU Commission. It reveals that various internal political positions prevail and that the role of power and conflict inside the EuropeanCommission is essential to understanding its policy proposals. Opening the "black box" of the Commission, the book identifies three ideal-types of internal position-formation. The Commission is depicted as motivated by technocratic problem-solving, by competence-seeking utility maximization orideologically-motivated policy-seeking. Specifying conditions that favour one logic over the others, the typology furthers understanding of how the EU system functions and provides novel explanations of EU policies with substantial societal implications.