J. David Singer passed away on 28 December 2009. He had a long career as a prominent scholar of international relations. He was a Professor of Political Science at the University of Michigan from 1964 and remained as a Professor Emeritus after his retirement in 2002. He served as President of the Peace Science Society (1972-73) and the International Studies Association (1985-86). However, he is best known as the founder of the Correlates of War Project, for over four decades the leading provider of data on armed conflict and, more recently, on a number of characteristics of states and dyadic factors used in the scientific study of war.