This monograph presents a brief review of the literature on integrating students with disabilities into mainstream educational programs. It begins by clarifying such terms as normalization, least restrictive environment, mainstreaming, and integration. It offers a historical perspective with a Canadian emphasis. The research on efficacy of integration is reviewed in terms of academic effects and social skills. Limitations of efficacy research are identified, including definitions of the handicapped population, educational intervention factors, and measurement of the dependent variable. Cost implications are considered. The importance of identifying effective practices is emphasized in a review of effective instructional practices and effective social skills instruction. Finally, six issues are recommended for future consideration before the adoption and implementation of widespread integration, including: integration cannot be viewed as a cost-saving measure, support services must be considered an integral part of any integration model, and Canadian teacher training programs should require all teachers in training to take special education courses. Appendixes provide additional information on the Cascade Service Delivery Model, the Modified Cascade Model, the Adaptive Learning Environment Model, the Integrated Classroom Model, and the Collaborative/Consultative Model. (23 references) (DB)