Since the creation of the first European community in 1951, the integration process has had several phases and characteristics. Without being able to assimilate it to a state constituent process, it has always been conditioned by the inability to really know where it was going, with economic and competence aspects prevailing. All the steps taken have been involved in essential debates without wanting to look at the elephant in the room: if we really want to constitute a European federal state, which would imply dissolving the current states. This book analyses, starting from the historical process, the keys to integration, the debates between federalist and confederalist positions, and the options for the future.