The development of EU policies from the Treaties of Rome in the 1950s to the Lisbon Treaty in 2009, which led to an "ever closer union" and ultimately to Brexit, are made comprehensible. This process shows that primarily political considerations led to Treaty changes. Both the political and historical background of the evolution of EU policies and the consequences for the UK and the EU as a result of the Withdrawal Agreement are presented in detail. Klemens H. Fischer is Professor of International Relations and Geopolitics at the University of Cologne. He is Vice President of the Austria Institute for European and Security Policy, Vienna, and member of the International Institute for Strategic Studies, London. He can draw on thirty years of experience in the field of European integration.