viii Preface language and addressed to a broader audience than the respective discipline of the author. We have also deliberately invited non-academic authors whose practical knowledge or civic engagement provides important insights. This format should be very useful for teaching purposes at undergraduate as well as graduate level. I sincerely hope that the book will also be read by practitioners and those often insultingly called ‘ordinary citizens’ who are interested in the future of Europe. In the past, organising such a conversation across a wide range of countries and academic disciplines would have been extraordinarily difficult. Today, this can be done on the Internet. All three debates in this book have been originally published online in the Forum section of the EUDO CITIZENSHIP observatory, which has recently expanded into GLOBALCIT, the Global Citizenship Observatory. The book also meets another important requirement for debates among citizens: they must be public and freely accessible to all. This was of course true for the original online publication of the three debates. Yet it is still exceptional for academic books to be freely accessible under a ‘golden open access’ licence. I am therefore very grateful to the IMISCOE editorial committee and to Springer for accepting to publish the book in their open access series. There is one way in which the debates in this book differ from the ideal of political deliberation among citizens in the public sphere. These debates do not aim to reach conclusions in the sense of a political decision taken by majority vote or a consensus achieved through the force of the better argument. They leave the initial question open. One reason is that it is really hard to make academic scholars change their views. The other and more important reason is that it is not for them to decide these questions. The aim of these debates is thus to inform readers about a wide range of views presented by authors who respectfully disagree with each other even after having made strong efforts to engage with each other. What the reader gets from this is, hopefully, different and also less time consuming than what she can learn from ploughing through thick academic volumes. The three debates collected in this volume concern all three dimensions of citizenship that T. H. Marshall identified in his seminal essay of 1949: the civil, political and social aspects of EU citizenship. The first debate was held in 2012, before the 2014 European Parliament elections and should be picked up again before the forthcoming ones in May 2019. It raises the question of why mobile EU citizens can vote in local and EP elections in their host EU member state, but not in national elections. For some authors this is a serious democratic deficit, for others it illustrates that the EU is not a federation but a union of states.