The European Union. Origins-Structure-Acquis is a textbook tailored to serve the needs of foreign students taking courses in humanities at Polish Universities. It was written by researchers from the Institute of International Relations of the University of Warsaw. The textbook is divided into three parts, covering crucial institutional and procedural aspects of the European Union. The first part serves as an introduction to the integration process. It looks at the genesis of this phenomenon, reforms of the European Communities undertaken over the years as well as the recent enlargements of the European Union. The pending reform based on the Treaty of Lisbon is also presented. Part two of the textbook is devoted to the political and institutional structure of the European Union. The centre of gravity remains with the model of European integration, based on the institutional system and legal order of the European Union.