Whoever Fights Monsters
My Twenty Years Tracking Serial Killers for the FBI

Robert K. Ressler (1937-2013) was a criminologist in private practice and the Director of Forensic Behavioral Services International, a Virginia based consulting company. Robert was an expert in the area of violent criminal offenders, particularly in the area of serial and sexual homicide. He was a specialist in the area of criminology, behavioral analysis, crime scene analysis, homicide, sexual assaults, threat assessment, workplace violence, and hostage negotiation.

Robert was a twenty-year veteran of the Federal Bureau of Investigation, serving sixteen years in the FBI's Behavioral Science Unit as a supervisory special agent and criminologist, retiring in 1990. He innovated many of the programs which led to the formulation of the FBI's National Center for the Analysis of Violent Crime. He became the first Program Manager of the FBI's Violent Criminal Apprehension Program (VICAP) in 1985.

He originated and directed the FBI's first research program of violent criminal offenders, interviewing and collecting data on 36 serial and sexual killers resulting in two text books, Sexual Homicide: Patterns and Motives and the Crime Classification Manual. He also coauthored his autobiography, Whoever Fights Monsters, Justice is Served, and I Have Lived in the Monster. He has been credited with coining the term "serial killer." Robert's books and real life experiences have been the inspiration for many books authored by Mary Higgins Clark and other authors and the films Red Dragon, Silence of the Lambs, Copycat, and The X Files.

He had lectured at and been a consultant to law enforcement agencies, universities, writers, television networks, and corporations in the U.S. and abroad. He appeared on many major television and radio networks and has been featured in numerous printed media articles in major newspapers and magazines, worldwide.