For decades, sovereignty was assumed to be a dying idea but it is reawakening, as witnessed by phenomena such as Brexit and self-determination processes at sub-State levels as in Scotland or Catalonia, the economic crisis in Greece and some other Mediterranean countries, and the rise of populisms across Europe. Some of these phenomena that nurture a renewed interest in sovereignty are somewhat connected to the European integration process and its crisis. In this context, describing, analysing and criticizing old and new uses of the notion of sovereignty seem a worthy, interesting and challenging undertaking. The opening sections of this work attempt to grasp the idea of sovereignty by questioning a traditional understanding of it (section 1), by distinguishing it from other close notions (section 2) and by identifying different types of sovereignty (section 3). After that, this report should be in a better position to deal with the question of whether the idea of sovereignty is vanishing in international and EU law and politics (sections 4 and 5). Once shown that the idea of sovereignty is still present, distinct visions of sovereignty in the context of the EU are offered (section 6). Some closing remarks on the transformative power of sovereignty are made in the last section.