This unique collection of research and practice papers highlight HMP Grendon’s groundbreaking and sustained contribution to our understanding of the role therapeutic communities have in effective interventions with offenders. It reveals the history and research behind HMP Grendon, one of the first prisons to develop therapeutic communities. It combines a mixture of quantitative and qualitative research papers, coupled with historical, theoretical and practice commentary. It features quantitative research based on unusually complete and extensive records, collected over an extended period and stored in Grendon’s database. It provides an international perspective with prominent figures from America and Holland.