Introduction
I would like to explain briefly how this research started. Initially, in the mid-1990s, while I was doing my PhD at the Graduate Institute of International Studies in Geneva, it was going to focus exclusively on collective violence and would remain within the parameters of traditional historical analysis. Subsequently however, intellectual curiosity incited me to look at other forms of extreme violence, in individuals this time, and more specifically in serial killers. To my great surprise (this had never been studied), it emerged that there were a number of similarities between the psychology of the serial killer and that of political extremists, the Nazi leaders in particular. Visibly, the field of study would have to be extended to encompass these findings, making use of all relevant scientific disciplines.