This book is divided into three sections. Entitled Critical Harm Reduction Policy: From Oppositional Social Movement to Institutionalised Public Health Policy, Part One encompasses a diverse array of issues relating to the cost/benefit analysis of harm reduction as measured in the terms of institutionalisation and (de-)politicisation. Part Two, Critical Harm Reduction Practice: Autonomy, Ideology, and Evidence-Based Interventions, consists of several concrete case studies concerning harm reduction practice in an array of (non-)traditional contexts. Comprised of a unique series of chapters that each interrogates a different issue relating to the philosophical underpinnings of harm reduction, Part Three is entitled Critical Harm Reduction Theory/Philosophy: Depoliticisation, Direct Action, and Drug/Service Users’ Experiential Knowledge. Although the emphasis of each section and corresponding set of chapters is remarkably diverse, several themes remain prominent throughout this book, including an overtly critical analysis of the multiplicity of contextual deployments of harm reduction, a recurring focus on elevating the value of experiential knowledge and the fundamentally important, central role of people with direct lived experience. Additionally, the centrality of direct action tactics in the innovation of user-based forms of harm reduction in policy, practice, and philosophically-based contexts are discussed.