Between 1933 and 1945 the Nazis murdered six million Jews along with gypsies, homosexuals, trades unionists and the disabled. This Holocaust has cast a shadow over society ever since.
How could such evil occur? How could so many be killed simply because of the groups they belonged to? What led people to murder others or else to support a murderous regime? These questions have haunted social scientists and lie at the root of modern social psychology.
Massacres in Rwanda, ethnic cleansing in the former Yugoslavia and the continuing slaughter in Darfur remind us that the issue has not gone away. What could be more important than to understand why and when people succumb to evil? And what could be more useful than understanding how to stop this happening?