Serial Killers: Understanding Mass Murder

Serial killers. Numerous books, movies, and video games revolve around this subject. There seems to be an obsession with these crimes and those that commit them.
Extreme killing: Understanding Mass Murder, answers questions such as; what is the difference between a serial killer or a mass murderer? Who commit these crimes? And what are the different motivating factors behind such crimes? We we even look for an answer to what is the difference between sociopaths and psychopaths? The book delves into an interesting subject of the difference of how these perpetrators feel empathy towards their victims, that is how many of these killers can logically understand empathy and sympathy and in fact use it to their own gain, for example Ted Bundy often