Joe Navarro was one of those police officers obsessed with their work, determined to protect ordinary citizens and punish evil with all their might. So, when he came across the case of Susan “Sue” Curtis, he was stunned by the injustice of this world. One day, the 15-year-old schoolgirl did not return from a conference, and her body was never found.

For many years, Joe had been carrying Sue's photo with him, and for even longer, he peered into the faces of passersby, trying to see in them this little girl brutally murdered by a maniac. Years later, as an FBI agent, Joe learned a terrible secret: a handsome young man was driving around campus in a Volkswagen the night Sue was kidnapped. It was the man named Theodore “Ted” Bundy, who would later confess to the murder of 35 other young women.

Joe couldn't figure out how this could have happened. How could a predator and serial killer find a place on one of the safest campuses for students? Why had Sue, this sweet and dear girl, fallen prey to him? But most importantly, what was going through the mind of a man who murdered 35 women in four different states, including very young girls?

Joe is certain that this one incident led him to work as a criminal profiler in the FBI's Tampa Division and later in the prestigious National Security Division Behavioral Analysis Program. Joe Navarro wanted to make a difference and save innocent potential victims like Sue. That’s why he decided to share some discoveries about certain personalities who hurt people the most.

Navarro believes that dangerous personality types are not only maniacs who commit mass murders in schools or terrorist attacks at airports. Yes, we talk about them a lot, but what about those who have killed just one child, just one roommate or partner? What about those people who don't commit murder but slowly extract money from loved ones, set up coworkers, abuse their partners, or sexually harass subordinates?

We should avoid those people who poison our lives and could potentially bring us harm. That doesn’t only include bodily harm because wounds are not always physical. Most people who hurt us also hurt us financially, emotionally, or psychologically. Who are they then?