Diego Gambetta is Professor of Social Theory at the European University Institute, while on leave from his Official Fellowship at Nuffield College, Oxford. Born in Turin, Italy, he received his PhD in Social and Political Sciences from the University of Cambridge, U.K., in 1983. From 1984 to 1991 he was Research Fellow at King’s College, Cambridge. Since 1992 he has been at the University of Oxford. He has been visiting professor at the University of Chicago, Columbia University, EHT in Zurich, Stanford University, Science Po and the Collège de France in Paris. His main interests are trust, signalling theory and its applications, organised crime, and violent extremists. He is the author of The Sicilian Mafia (1993), Streetwise (2005), La Pègre Déchiffrée (2010) and Engineers of Jihad (2016). In 2000 he was made a Fellow of the British Academy.