In genocide studies, perpetrators, victims, and bystanders is an evolving typology for classifying the participants and observers of a genocide. The typology was first proposed by Raul Hilberg in the 1992 book Perpetrators Victims Bystanders: Jewish Catastrophe 1933–1945. Anthropologist Alexander Hinton credits work on this theory with sparking widespread public intolerance of mass violence, calling it a "proliferation of a post-cold war human rights regime that demanded action in response to atrocity and accountability for culprits.". The triad is also used in studying the psychology of genocide. It has become a key element of scholarship on genocide, with subsequent researchers refining the concept and applying it to new fields.
Initial analyses of atrocities such as the Holocaust discussed these events simply as violence by perpetrators against victims. Scholars added the category of "bystander" to include people who impact, and are impacted by, mass violence but who are not clearly perpetrators or victims. Even with this added complexity, most genocide research focuses on perpetrators, in part because evidence of their behavior is most accessible to scholars. While research about bystanders' role in violence dates to the mid twentieth century, research about their role in genocide is more recent. Just as emerging research has added complexity to the triad as a whole, it continues to recognize nuance in each of the three roles.
