This report, following more than a decade after the National Center on Addiction and Substance Abuse's (CASA's) initial analysis, finds that despite greater recognition of the problem and potential solutions the population of substance-involved inmates crowding the Nation's prisons and jails, and the related costs and crimes, has been allowed to increase. In addition, the report shows that 1) science has demonstrated that risky substance use is a public health problem and dependence is a medical problem, 2) failure to prevent and treat the condition increases crime and its costs to society, 3) public opinion supports treatment for substance-involved offenders, and 4) a range of cost effective alternative exist. This report is designed to demonstrate that investment in evidence-based prevention and treatment for the criminal justice population is fiscally sound and politically palatable. Highlights of recommendations in the areas of the criminal justice system and Federal, State, and local governments include: 1) use appropriately trained healthcare professionals; 2) eliminate mandatory sentences that eliminate the possibility of alternative sentencing and/or parole, and expand the use of supervised release; 3) keep jails, prisons, and other correctional housing and facilities free of tobacco, alcohol, and other drugs; 4) require that addiction treatment be provided in criminal justice settings, that it be medically managed and pharmacological treatments be available; and 5) educate public officials about the nature of addiction, the effectiveness of treatment, the social and economic benefits of providing treatment to offenders with substance use disorders and the importance of tracking outcomes. This study, an update by CASA to its 1998 study, analyzed data on inmates from 11 Federal sources, reviewed more than 650 articles and other publications, examined best practices in prevention and treatment for substance-involved offenders, reviewed accreditation standards, and analyzed costs and benefits of treatment. Figures, tables, appendixes A-B, notes, and bibliography