399 In memory of Pietro Barcellona (Antonio Palazzo) Issue 2013 of Review “Diritto e processo” in memory of Pietro Barcellona (Catania, 1936, 12th March – San Giovanni la Punta, 2013, 6th September), University professor, italian politician, philosopher, jurist, writer, mentor and friend. Pietro Barcellona was a Professor of Private Law and Philosophy of Law at the Faculty of Law at the University of Catania. From 1976 to 1979, he was a member of the “Consiglio Superiore della Magistratura”. He graduated in Law in 1959 and in 1963 he become Lecturer in Private Law at the University of Messina. He was a member of the “Centro per la Riforma dello Stato”, founded by Pietro Ingrao. In 1979 Pietro was elected Deputy of the Italian Communist Party and, in this quality, he was a member of the Justice Committee of the “Camera dei Deputati” until 1983. He was the author of ninety-four publications between books and papers. At the end of his life, he was appointed Professor Emeritus of Philosophy of Law at the University of Catania. He was also a painter. Pietro Barcellona died at the age of 77 on 2013, 6th September. In particular, in this occasion, I and all members of this Review wish to commemorate Pietro Barcellona and his studies of Private Law, with specific reference to the “errore” in contracts (Profili della teoria dell’errore nel negozio giuridico, Milano, 1962), where the author – among the earliest – underlines the importance of the “causa di attribuzione”, which is protected by several juridical tools: “errore”, “rilevanza del motivo”, “presupposizione”, “azione di arricchimento senza causa”. The aforesaid concepts – confirmed and developed also afterwards (Note critiche in tema di rapporti fra negozio e giusta causa dell’attribuzione, in Riv. trim. dir. proc. civ., 1965, p. 11 ss.) – have represented the necessary condition of the so called theory of “causa in concreto”, nowadays accepted by the majority of scholars and confirmed by the jurisprudence of the “Corte di cassazione”, also “a Sezioni unite”.