On the 14th of December 2017, the Re-Bel initiative invited the participants in its 15th public event to reflect on the following questions: “Are nationalism and/or patriotism tolerable? Are they legitimate? Might they even be indispensable to the smooth functioning of a democratic polity? If so, at what level(s) and under what conditions? And what follows as regards the drawing of borders and the allocation of sovereignty?” We were then in the immediate aftermath of the Catalan independence referendum, and half of the event focused on the clash between Catalan nationalism and Spanish nationalism, with the active participation of one member of the Catalan government in exile, Professor Clara Ponsati. But the purview of the event was broader. The questions listed above are no less present in the Brexit process and throughout the debate on European integration. And they are of course at the core of many discussions about the future of Belgium. The present e-book collects a written version, sometimes significantly expanded, of most of the presentations at the public event. Louis Vos offers an historical introduction to the concepts of nation and nationalism. The contributions by Eric STORM (University of Leiden) and Clara PONSATI (University of St Andrews, formerly education minister in the Catalan govenment) highlight a number of features of the historical background of today’s Catalan situation that help understand the sharp differences between the respective narratives of Catalan and Spanish nationalists. Vincent SCHELTIENS (University of Antwerp) and Bart MADDENS (University of Leuven) each present their own analysis of the Catalan conflict and spell out what they see as the main similarities and differences with the Belgian situation. In a (particularly popular) piece previously published on his blog, Paul DE GRAUWE (London School of Economics) draws a parallel between the motivation and consequences of Catalan independence and Brexit. Finally, Sophie HEINE (University of Oxford) argues for a sovereign ...