The manner in which time is institutionalized is critical to how a political system works. Terms, time budgets and time horizons of collective and individual political actors; rights over timing, sequencing and speed in decision-making; and the temporal properties of policy matter to the distribution of power; efficiency and effectiveness of policy-making; and democratic legitimacy. This book makes a case for the systematic study of political time in the European Union (EU) - both as an independent and a dependent variable - and highlights the analytical value-added of a time-centred analysis. The book discusses previous scholarship on the institutionalization of political time and its consequences along the dimensions of polity, politics and policy; reviews dominant perspectives on political time, which centre on power, system performance and legitimacy; and presents case studies that illustrate the importance of time in the governance of the EU. This book was original published as a special issue of Journal of European Public Policy.