Prevention curtails freedom: cancer prevention entails not smoking; accident prevention entails putting pills in childproof containers; crime prevention entails not stealing things and hitting people. Prevention is usually seen as quite unexciting. Preventive medicine is less dramatic than surgery, crime prevention than detection. However, people doing less of one thing are free to do more of another: obesity prevention makes exercise possible and crime prevention frees up time, money and energy to invest elsewhere. This book seeks to enliven the topic of crime prevention by looking at pro-social behaviour alongside crime, to think of improving the quality of life by both deflecting people from the experience of crime - either as perpetrators, victims, or worried bystanders - and nudging them towards collaborative and altruistic behaviour; by changing things, places and people in ways which push people from crime and pull them towards active citizenship. Research and practice is reviewed taking this wider view of crime prevention.