Mark Osiel’s work seek to show how we may improve the law’s responses to mass atrocity by better understanding its organizational forms and social dynamics. Osiel has served as consultant in several, high-profile international trials and advised the U.S. Department of Defense on anti-terrorism prosecutions. He regularly addresses international organizations and governments in post-conflict societies on issues of transitional justice. He was director for international criminal and humanitarian law at the T.M.C. Asser Institute, in The Hague, and is an occasional media commentator on legal aspects of contemporary armed conflicts. His scholarship can be found in the nation’s leading academic journals and in the several books he has authored on the topic.