Those who have studied psychology, or been around violent people, would likely find it remarkable that almost all major criminological theories are “general” and that the authors do not attempt to distinguish violent offenders from less serious offenders. Many criminologists undergo their training in sociology, so it is easy to attribute their acceptance of a “unidimensional criminality” to that training. Some authors have concluded that violent criminals are simply criminals who happen to commit violent acts, but we believe that this assumption is unmerited and reductive. The ascendance of Moffitt’s dual taxonomy of life-course-persistent versus adolescence- limited offenders made an important contribution because at least criminologists today are trying to predict serious problems, not just run-of-the-mill delinquency like underage drinking, petty theft, or vandalism. Nonetheless, there is clear evidence that the overlap between persistent offending and violent offending is not complete, and the field of criminology continues to exhibit complacency about disentangling the causes of violence in spite of the fact that the causes of other forms of crime are less important to the public and to policymakers. Combing through both the scholarly and popular literature, we find a plethora of case study examples of serious, violent offenders whose life histories and psychological states are notably different from the average person and from other offenders. In the empirical literature, examples abound where violent offenders differ from nonviolent ones. In light of such evidence, the lack of a strong statement about the etiological differences between violent and nonviolent crime is bewildering. It is our goal in this book to make that statement and to evaluate the empirical evidence to see if our instincts are correct, or not.
We draw inspiration from evolutionary-ecological theories that would predict that frequent violence can become “normal” under certain conditions, and those conditions might be quite different than the conditions that bring about a high incidence of expropriative behavior. We want to better understand the robbers and murderers, thugs and gangsters so that we can disentangle the facts in their lives that lead them to hurtful, sometimes vicious behavior that may destroy others, but also themselves. We also want to understand violence in order to better protect victims, battered women, and beaten children. Many industrialized countries in the world are currently experiencing an unprecedented crime decline. However, just because overall rates of violence are lower than they were a decade or two ago does not mean that violence, preventable violence, isn’t touching the lives of many people every day.