Preventive coercive measures are an increasingly common and controversial feature of the legal landscape in many countries. Examples include the preventive detention of 'dangerous' individuals after the expiration of their sentences, the involuntary commitment of 'dangerous' individuals to mental institutions purely to protect the public and the preventive detention of suspected terrorists not charged with any crimes. The practice raises a range of important and inter-related legal, criminological, moral, sociological and forensic-psychiatric questions. For instance, it is generally based on...