The Theory of Democratic Integration, which will be presented in this treatise, is the first political theory to account for the dual character of the EU as both a Union of States and a Union of Citizens. The new theory brings about a revolutionary breakthrough in EU research as it replaces the traditional Westphalian paradigm of states with the civic perspective of democracy and the rule of law. From this perspective there is no point in governing an organisation of democratic states in an undemocratic manner. At the same time it is equally self-evident that, if two or more democratic states agree to share the exercise of sovereignty in a number of fields with a view to attain common goals, the organisation they establish for this purpose should be democratic too. The Copernican revolution, engendered by the theory of democratic integration, is not only of academic interest. It also has great practical consequences. The first concrete result of the new theory is that it provides for the first-ever scientific definition of the EU. Moreover, it overcomes the longstanding stalemate in the debate about the future of Europe. Finally, it empowers the EU to tell the Story of Europe from the citizens' perspective in a captivating narrative as the journey from a soulless EU to a living European democracy.