Book excerpt: What Works in Corrections, first published in 2006, examines the impact of correctional interventions, management policies, treatment and rehabilitation programs on the recidivism of offenders and delinquents. The book reviews different strategies for reducing recidivism and describes how the evidence for effectiveness is assessed. Thousands of studies were examined in order to identify those of sufficient scientific rigor to enable conclusions to be drawn about the impact of various interventions, policies and programs on recidivism. Systematic reviews and meta-analyses were performed to further examine these results. This book assesses the relative effectiveness of rehabilitation programs (e.g., education, life skills, employment, cognitive behavioral), treatment for different types of offenders (e.g. sex offenders, batterers, juveniles), management and treatment of drug-involved offenders (e.g., drug courts, therapeutic communities, outpatient drug treatment) and punishment, control and surveillance interventions (boot camps, intensive supervision, electronic monitoring). Through her extensive research, MacKenzie illustrates which of these programs are most effective and why.