Preventive Justice looks at the use of coercive preventive measures by the state, both within and beyond criminal law. Examining preventive laws, measures, and institutions in and outside the criminal law, it explores the justifications given for using coercion to protect the public from harm. This is not, and could not have been, the last word on the subject. As the authors themselves acknowledge in their conclusion, many of the principles they identify are open-textured in nature and require to be worked through in detail in relation to each sphere of application, while questions of weight, tensions and conflicts may also pose difficulty. The principles will, however, allow academics and policymakers to identify more clearly just what questions should be asked and what factors should be relevant to individual decisions and broader structures, something well illustrated by the authorsâ criticism of the Independent Reviewerâs reliance on considerations of economy in evaluating terrorism prevention and investigative measures. The authorsâ work is simultaneously groundbreaking and of direct practical application, and deserving of considerable praise.