In this book, FBI veteran and founder of the FBI's Serial Killer Profiling Unit, John Douglas uses his vast knowledge of psychological profiling in order to help the reader understand a criminal's mind. Douglas writes about his own analysis of some very interesting crimes. By using criminal personality profiling techniques he developed while stalking more current killers, Douglas provides a fresh, outlook on some of the most disturbing and mind-boggling crimes of the century and in the process proves that sometimes reality can be more horrifying than fiction.

     He sheds new light on San Francisco's Zodiac Killer, the Black Dahlia murder, Bambi Bembenek, the Boston Strangler, and the continuing mystery of who killed 6-year-old JonBenét Ramsey. He goes through eight different cases, providing very in-depth analysis of each one. At times Douglas reveals who he thinks committed the crime and at other times he simply narrows down who is not the killer. 

     In the JonBenét mystery (in which Douglas was hired by the Ramseys to find the murderer), he presents a convincing case for why he believes the girl's parents are not the ones guilty of murder.