Deterrence is at the heart of the preventive aspiration of criminal justice. Deterrence, whether through preventive patrol by police officers or stiff prison sentences for violent offenders, is the principal mechanism through which the central feature of criminal justice, the exercise of state authority, works - it is hoped -- to diminish offending and enhance public safety. And however well we think deterrence works, it clearly often does not work nearly as well as we would like - and often at very great cost. Drawing on a wide range of scholarly literatures and real-world experience,...