The article traces the history of mass segregation of handicapped students in U.S. public schools, notes the advent of the concepts of mainstreaming and least restrictive environment, and analyzes such ramifications of mainstreaming as increased numbers of handicapped students in college and re-emergence of "tracking" or ability grouping. (CL)

Most of the principals (82 percent) considered the most effective placement to be a combination of regular class and part-time special education. Only 6.4 percent regarded full-time regular class as most effective, while 10.1 percent favored full-time special class placement. (DB)