Director of the Historical Memory Commission for the National Commission of Reparation and Reconciliation (CNRR ). He is a historian graduated from Essex University (UK) and has a doctorate in Political Sociology from the Ecole De Hautes Etudes in Paris, France. He is also a Professor Emeritus from the Institute of Political Studies and International Relations (IE PRI ) at the Universidad Nacional de Colombia, and has written and edited numerous books including: Bandoleros, Gamonales y Campesinos (co-written with Donny Meertens, Ancora, 1983); Guerra y Política en la Sociedad Colombiana (Ancora, 1991); Grandes Potencias, el 9 de abril y la Violencia (Planeta, 2000); Museo, Memoria y Nación (compiled with Maria Emma Wills; Museo Nacional/Iepri, 2000); Guerras, Memoria e Historia (IC ANH/IE PRI , 2003). He coordinated the report by “violentologists” presented to the Barco administration: Colombia: Violencia y Democracia (1987) and co-edited Violence in Colombia (Scholarly Resources, 1984), and Waging War and Negotiating Peace: Violence in Colombia, 1900-2000 (Scholarly Resources, 2001) with Charles Bergquist and Ricardo Peñaranda. In collaboration with Eric Lair, he edited Violencias y Estrategias colectivas en la region andina (Norma/Iepri, 2004) and is co-author of the collection Nuestra Guerra sin Nombre (Norma/ IE PRI, 2006). He was a guest professor in the History Department at Duke University (USA); at the Sorbonne, the Ecole De Hautes Etudes in Paris; the Institute for Latin American Studies at the University of Texas, and at University College of London.