This major new book brings together leading researchers in the field in order to describe and analyse internationally significant theoretical and empirical work on offender supervision, and to addressing the policy and practice implications of this work within and across jurisdictions. It arises out of the collaborative work of a new international network focusing on this area - the Collaboration of Researchers for the Effective Development of Offender Supervision (CREDOS). The starting point of the book is that although the 'what works' movement in probation research had achieved a great deal, new impetus was necessary to allow the effectiveness agenda to develop beyond its historical emphasis on the principles of effective programmes and into a much wider range of questions and issues.These questions and issues arise both from within effectiveness research itself (for example, about the role of workers' practice styles and approaches and about the organisational contexts of programme work) and from research on desistance from offending and how it can be best supported (for example, about the significance of personal and professional relationships in the process, and about the importance of developing social capital). Key themes addressed in the book are as follows: how best to measure effectiveness in offender supervision; the nature and features of effective offender supervision; the characteristics, styles and practices of effective offender supervisors; the qualities and features of effective relationships between offenders and those that work with them; and, the social, political, cultural, organisational and professional contexts of effective offender supervision and how these contexts impact upon it. This book will be essential reading for academics, undergraduate and postgraduate students, policy makers, managers and practitioners interested in offender supervision.