This book is the result of an attempt to impose a structure on my reading and thinking about services of general economic interest (SGEI). This is one of the key categories in which public services are addressed in EU law. SGEI is a theme that I have been interested in since I prepared my PhD thesis on EU competition law and industrial policy at the European University Institute in Florence in 1991–6. Although it was not the topic of that thesis, I did use the telecommunications sector as a case study, which has remained a source of inspiration regarding the categories of SGEI and universal service in the context of liberalization of public services. Since then, as I argue in this book, SGEI have only become more pertinent with the growing impact of EU law, and the increasing market orientation of public services (including not just the utilities but welfare services as well), within the constraints of the rules and exceptions of EU law. At the same time a citizenship dimension is emerging, although its shape remains indistinct. Evidently, I could not have completed this book without the generous help of others. I am particularly grateful to José Luis Buendia Sierra, Jim Davies, Leigh Hancher, Dairmuid Rossa Phelan and Nicolas Rennuy who have freely provided their time and expertise, suggested materials, as well as read and commented on the text as a whole. I am grateful to them for this essential contribution even though I realize that I may not always have done full justice to their remarks. Able and timely research assistance was provided by Tilburg law students Charlotte Aardoom and Rina Verbakel. Evidently I alone am responsible for any remaining flaws in the text.