His primary area of expertise is in ethnic conflict and
genocide. His interest in the topic derives from his family's experience in Europe, as well as from his field work in
Nigeria in 1964–65, just before the onset of the
Nigerian Civil War. The story of his family's shared survival during the Holocaust is told in
False Papers (University of Illinois Press, 2000), which was a finalist for the 2001
National Jewish Book Award. Among his other books are,
Revolution and Genocide: On the Origins of the Armenian Genocide and the Holocaust (University of Chicago Press, 1992/6). He has published (with Howard Wolpe, eds.),
Nigeria: Modernization and the Politics of Communalism. (East Lansing: Michigan State University Press, 1971). His articles have been published in the
American Political Science Review, Comparative Studies in Society and History,
Holocaust and Genocide Studies, and elsewhere. == References ==