Increasingly, pressure is being put on mental health professionals to better predict which individuals are at the greatest risk of committing acts of violence. There is also great demand for clinicians to employ treatment strategies aimed at preventing violent and aggressive behavior. In this book, we will discuss what is known about violent and aggressive individuals, including neural circuitry and possible genetic influences underlying violent and aggressive behavior as well as evidence- and practice-based treatment strategies that may reduce such behavior. Given the fact that mental illness may increase the risk of violent or aggressive behavior, yet with only a small subset of mentally ill patients exhibiting this disturbing behavior, it is crucial to be able to predict which individuals are more likely to be violent or aggressive and take measures to prevent violent acts.