A review is presented of the components and underlying correctional models of IPS programs in 31 States. Descriptions and preliminary evaluative data suggesting program effectiveness (recidivism and costs/benefits) are presented for programs in Georgia and New Jersey. Change management is discussed with reference to the design and implementation of an IPS program in Massachusetts. Also described is the planning and preliminary implementation of an ISP pilot project in Oregon. Characteristics of house arrests programs are delineated. An examination of the use of electronic monitors is provided, together with an analysis of constitutional and other legal issues associated with their use in IPS programs. A review of evaluative research shows that IPS programs are cost effective compared to incarceration and to regular probation. The need for methodologically rigorous research into IPS is discussed, particularly in the areas of offender classification and the evaluation of the effects of different interventions on particular types of offenders. Finally, the history of probation is reviewed, and it is noted that IPS represents a return to earlier forms in which probation was truly an alternative to imprisonment and in which emphasis was placed on careful monitoring, control and rehabilitation. References, notes, figures, and tables. For individual articles, see NCJ 111579-111587.