How can we understand the stories that motivate the murderous behavior of Islamic groups such as Isis, Al Queda, and Boko Haram? In my last podcast I suggested that such organizations have always been a part of the human condition and associated with many religions and nationalistic movements. Today I shall take another trip down memory lane and discuss the cancers that arose within Christianity and why Islam is now such fertile ground for the modern versions of these horrors. I will spend time discussing the rise of Hitler and the Nazis which also might cast light on why deadly cancerous ideas get organized and gain traction among large groups of people. Finally, I will begin to discuss some notions as to the factors that prevent these cancers from developing.