The question of dangerousness--how it should be defined and punished and the ethical dilemmas associated with it--is a recurring theme of modern policy. In this powerful and important book, John Pratt addresses this question by explaining how dangerousness first became an object of penological discourse and why it has since remained so. Pratt sees the late 19th century as an important turning point; earlier concerns about the threat posed by the dangerous classes gave way to a new set of concerns about dangerous criminals. Drawing on material from Australia, New Zealand, England, the U.S., and Canada, the author argues that dangerousness is a particular creation of modernity that began when the concept of risk and its attendant strategies of management found their way into the social fabric. Ultimately, the dilemma of dangerousness is seen as political rather than ethical.