Like no other professional group, physicians were involved in the National Socialist racial and extermination policy. Physicians participated as clinicians, scientists and experts in forced sterilizations, the killing of patients (NS euthanasia) and human experiments in the concentration camps. Doctors were actively involved in the Holocaust and the genocide of Sinti and Roma, almost without exception voluntarily. The focus of the volume is the question of how doctors became perpetrators in the "Third Reich". The history of reception of these disastrous events, which continues to this day, is also discussed. The authors of the volume use approaches from the history of mentality, culture and ideas; there are also socio-psychological attempts at interpretation and (group) biographical analyses.