This student text covers all aspects of working with drug and substance misusers, including the history and changes in policy on substance misuse and the differences between working with young and adult clients. Recent government initiatives and legislative changes are carefully outlined, while discussions on why people take drugs, the policy implications of harm reduction and abstinence approaches to substance use/misuse are related back to practice so that readers understand how to engage with the client group and the reasons for varying success across treatment approaches.