This chapter considers executive branch politics in a number of European democracies. It addresses the nature of parliamentary democracy and compares it with other forms of democracy. For example, it looks at separation-of-powers systems using the principal–agent framework of Chapter 2. The chapter examines in detail the link between parties and institutions in order to understand the process of government formation and government collapse. It begins to consider the foundations of the process of law-making which is relevant for the remainder of the book.