Could it be that mass murderers are not vile monsters but instead desperate people afflicted by an addiction that many of us could fall prey to if we harbor a grievance? In The Science of Revenge, James Kimmel, Jr. explains the track that can take any of us from pain to destructive action – and how it can be interrupted.

We have probably all experienced the pleasure of imagined retaliation for some past hurt or pain. Kimmel did. The bullying he experienced as a teenager led him to the brink of a violent act that would have devastated his life had he not stopped himself. What he wasn’t able to stop was a growing pleasure in seeking new ways to act on his anger, and eventually, his craving led him to join the professional revenge business – as a lawyer. There, he saw that people were willing to incur great costs to punish, even without receiving any material benefit in return. He helped his clients maximize retaliation just for the satisfaction it gave him. “Justice,” as the word is commonly used, became legalized revenge. Just as a drug addict craves a fix, so Kimmel found himself needing more. But one day the thrill crashed. Immediately, he decided to stop, and dedicated himself to finding out what it is that drives us along this pleasurable but deadly pathway.

By teaming up with top-level research institutions and studying the life patterns of notorious killers from the past, Kimmel found the simple cause: when we are treated unfairly and harbor anger, guilt, or shame, the pain network in our brain is activated, and it hurts. Angry thoughts of revenge release dopamine, which covers up the pain and brings pleasure, though only temporarily. A crash then spurs us to action, to hurt those responsible. Some people can’t stop and are willing to harm not only themselves, but also bystanders in the pursuit of revenge.

Thankfully, the same research also verified an ancient cure – forgiveness. The same brain scans that showed activation of certain areas during anger showed the reverse with forgiveness. His conclusion: “This makes forgiveness a powerful brain-biological process for addressing revenge addiction – if we use it.” To this end, the book offers a remarkable tool called “The Nonjustice System,” which is available online.

Readable and at times humorous, the book confronts the mystery of the continuous stream of violence we see in our country and presents an actionable solution. Scarlett Lewis, a mother whose six-year-old son was murdered in the 2012 Sandy Hook Elementary School shooting, has found Kimmel’s approach invaluable. She has spent years studying what motivates shooters and uses her findings today to teach kids to “Choose Love,” which is also the name of her organization. “This book cracks the code,” she says, of why individuals commit violence. “Up until now, we haven’t known what causes the grievance in most cases. Without a why, how can we solve it? Kimmel has done just that.” Lewis is currently working with the author to incorporate his findings into her school curriculum, which is being taught in all fifty states and 132 countries. With the mystery of senseless violence so articulately dismantled, we have no reason not to act on this knowledge.