Offender supervision in Europe has developed rapidly in scale, distribution and intensity in recent years. However, the emergence of mass supervision in the community has largely escaped the attention of legal scholars and social scientists more concerned with the mass incarceration reflected in prison growth. As well as representing an important analytical lacuna for penology in general and comparative criminal justice in particular, the neglect of supervision means that research has not delivered the knowledge that is urgently required to engage with political, policy and practice communities grappling with delivering justice efficiently and effectively in fiscally straitened times, and with the challenges of communicating the meaning, legitimacy and utility of supervision to an insecure public. This book reports the findings from a survey of European research on this topic, undertaken during the first year of a European research network that spans twenty countries. As such, it provides the first comprehensive review of research on offender supervision in Europe, opening up an important new field of enquiry for comparative social science, and offering the prospects of better informed democratic deliberation about key challenges facing contemporary justice systems, policymakers and practitioners, and the societies they seek to serve.