What is genocide? How do we define it? Where does it come from? Is it a modern phenomenon? What is the role of state building in genocide? What is its relationship to war, colonization, and imperialism? These are the questions that are at the heart of scholarly debates and research in the burgeoning and multidisciplinary field of genocide studies, which encompasses history, political science, sociology, psychology, social psychology, law and legal studies, anthropology, health sciences, and others. If the questions seem simple enough, the answers are anything but and depend on who is asked. Regardless of questions or answers, the historical study of genocide and atrocity is well suited to the study of war and society, encompassing interdisciplinary factors that extend beyond traditional methodologies in military history.