I first heard about Felix Oppenheim from my friend and colleague Alessandro Passerin d"Entreves, who held the chair in "Doctrine of the State" at Turin University and was simultaneously giving a course at Yale in the United States. As I see from the first letter in my long and continuous correspondence with Oppenheim, dated 26 October 1963, d"Entreves had spoken to him about our Institute of Political Science, and had made him all the more keen to participate in our discussions. He looked forward to meeting me the following year in Turin, and I answered him on 6 November thanking him for choosing Turin as the first port of call in his teaching visit to Italy. I also expressed my admiration for his excellent knowledge of Italian – the more so, I added, as I had never really managed to learn English properly. Finally, I told him that I had just received his recent book on freedom, which both d"Entreves and I wished to make known in Italy, albeit for different reasons.