Experienced legal academics and mental health professionals explore the current approaches to "dangerousness" and preventive detention. The defining characteristics of those deemed dangerous by society vary according to culture, place, and time, and the contributors to this text have gathered to analyze the policies and practices related to current out-groups such as sex offenders, suspected terrorists, and young offenders in the United States, Scotland, England, and Australia. Dangerous People is the result of their research, workshopping, and writing. The text is organized logically and begins with a section on Parameters that explores the international human rights and legal limitations related to preventive detention schemes. It moves on to Policy, where contributors examine legislative policy, and Prediction, or risk assessment, especially in terms of violent crimes in youth. The section on Practice focuses on recent schemes to prevent re-offending. This text is indispensible as a resource that deals with the practical issues surrounding preventive detention and supervision schemes, the assessment of the risk of future harm in offenders, and different programs and sentencing options for high-risk offenders with mental illnesses. It contains case examples that bring real-life issues to light and sets forth an agenda to provide effective ways to protect communities from harm.