Hagan is the winner of the 2009 Stockholm Prize in Criminology. His research has spanned many different issues, including women in the legal profession, the migration of Vietnam War resisters to Canada, and the relationship between poverty and crime. Most recently, his research has focused on international justice in the aftermath of genocide and war crimes, including the operation of international war crime tribunals in the Balkans and the training of Iraqi judges to deal with trials involving torture. His most recent book, co-authored with Wenona Rymond-Richmond, is entitled Darfur and the Crime of Genocide. Based on interviews with thousands of refugees collected by the State Department, this book provides a first-hand account of the events in Darfur and moves genocide to the center of criminological analysis.