Systems, love, philosophy, science, end-means, anthropomorphism, economy, action, success, separation: these are the main theoretical themes of that strange and extraordinary dialogue that developed between Eugenio Colorni and Altiero Spinelli in the Ventotene island (1939-42). They represent an easily accessible, interdisciplinary, iconoclastic, liberating, and fantastic intellectual feast under extreme conditions of confinement imposed by the fascist regime. They developed hand in hand with the political discussion that, with the contribution of Ernesto Rossi and Ursula Hirschmann, gradually unveiled the well-known political Manifesto for the unification of Europe.