With nearly five million offenders under community correctional supervision, the time has come to seriously question the efficacy of probation and parole. In terms of resource expenditures, public safety, recidivism reduction, and offender outcomes, there is ample room for improvement. Unfortunately, most current offender supervision practices are of limited value. The balance of treatment and control espoused by most community corrections agencies is ineffective, often resulting in nothing more than bureaucratic case management. Moreover, both of these models of probation and parole as practiced are largely defunct. In the first instance, efforts to reduce offender propensity often fail to adopt the principles of effective correctional intervention. In the second, efforts to deter offenders from misbehaving have produced little more than an increase in technical violations of supervision conditions. Accordingly, a new framework for probation and parole supervision is sorely needed. Determining how to reduce recidivism among community-supervised offenders leads us to consider why criminal acts occur. The answer is that two conditions must be present: An individual must have the propensity to offend and must also have the opportunity to offend. A considerable amount of research has been dedicated to discovering the criminogenic needs that must be targeted for change in order to reduce criminal propensity. By contrast, relatively little is known about what offender supervisors might do to reduce the crime opportunities of probationers and parolees. Notably, Cullen, Eck, and Lowenkamp (2002) propose that environmental criminology can help guide the development of innovative strategies that limit supervisees' chances to offend. They reconceptualize probation and parole supervision as "environmental corrections," a model in which officers would work to enhance the informal social control offenders are subject to, reduce offenders' access to crime opportunities, and restructure offenders' routine activities with prosocial influences. The aim of this dissertation is to elaborate on these ideas, developing a new strategy for offender supervision that is based on opportunity reduction. In so doing, the following roadmap is taken. Chapter 1 outlines the drawbacks of current probation and parole practices, demonstrating the limited effectiveness of existing treatment and control orientations to offender supervision. Chapter 2 introduces the components of environmental criminology, discussing how the advances of crime science have produced practical programs that reduce crime opportunities. Chapter 3 applies these theories to offender supervision, discussing strategies for preventing probationers and parolees from encountering situations where there are high-risk chances to commit crime. Chapter 4 presents assessment technologies for community corrections officers to use in discerning where, when, why, and with whom offenders commit crimes, developing methods for using this information to reduce the actual crime opportunities of supervisees. Chapter 5 demonstrates how cognitive-behavioral techniques can be used to help probationers and parolees recognize, avoid, and resist available chances to offend. Chapter 6 identifies how community corrections authorities can partner with the police to further limit supervisees' crime opportunities. In closing, Chapter 7 features eight lessons learned from the current elaboration of environmental corrections supervision that can help to make probation and parole work.