This text aims to present a model of intervention for use by clinicians working with substance-abusing criminal offenders, and students interested in understanding the drug-crime relationship. The author outlines a programme of change divided into three phases. The first or foundational phase of intervention is designed to arrest the drug and criminal lifestyles. This is followed by a phase in which clients are instructed in basic social, coping and thinking skills. The third and final phase involves resocialization in which clients are encouraged to develop a lifestyle incompatible with their continued involvement with drugs and crime. Two case studies are presented in the final chapter in an effort to demonstrate how this model can be applied with real-life clients.