Covering both the political executive and the administrative executive at the EU institutional level, the book analyzes their relationship with national executive power, and traces the historical evolution of executive order in Europe from the Peace of Westphalia through classic inter-governmental organizations to the allegedly unique EU framework. The book's analysis covers both the formal legal structure of the Union and the evolution of the EU's living institutions in practice. The picture presented is of a fragmented, cluttered and complex European executive space, resistant to radical constitutional reform and in need of a more nuanced understanding of the different forms of executive power required by different political aims and modes of decision-making.