The focus of the analysis is on summarizing what is known about people who are most likely to kill for a cause and how this knowledge can be used to deter and discourage terrorist actions. The basic rationalizations employed by terrorists in their attacks against civilian populations are reviewed and the oft-cited charge that terrorists “must be crazy” is refuted. In fact, the author observes that a certain amount of psychological resilience and philosophical resolve tends to characterize political terrorists that generally lack the antisocial personality characteristics found in many chronic offenders. The author notes that a terrorist lifestyle is a difficult one and, as such, a terrorist requires a combination of several positive psychological qualities, such as reliability, trustworthiness, and loyalty. Terrorist typologies are reviewed, which include the typologies of “crusaders, criminals, and crazies,” American and International terrorists, secret service profiles of terrorists, and fanaticism and destructive cults. The author next considers terrorist personality traits, types, and disorders, focusing specifically on paranoid, narcissistic, borderline, avoidant, dependent, histrionic, schizoid-schizotypal, and antisocial personality disorders as particularly well-suited to terrorist ideologies and tactics. While psychological principles alone cannot solve the problem of terrorist intelligence gathering, having knowledge of the possible psychological components of terrorists will certainly help inform law enforcement and psychological practices in regard to counter-terrorism strategies. References