Anarchist Emma Goldman refers to ‘those who have studied the character and personality’ of politically violent men as if such a group of scholars existed. It is not clear to whom Ms Goldman is referring. If, in 1930, there existed a cadre of psychologists who studied the ‘character and personality’ of politically violent men, they apparently failed to publish their results. However, at the time of writing, a decade into the twenty-first century, there is indeed a cadre of scholars of the psychology of terrorism, and a body of literature that earnestly wrestles with the troubling question: ‘Why do individuals resort to political violence?’ Terrorism is arguably a major threat to global security. Some fear that the dreaded nexus of terrorist intention and nuclear capability may be the next occasion for nuclear holocaust. It would seem to be very much in the interests of peoples and nations to prevent terrorism. It is possible that knowledge of terrorist psychology might contribute to that project, so it would seem very much in the interests of peoples and nations to understand why terrorists do what they do.