A study was conducted to develop baseline information on special education early intervention programs. A review of the literature revealed the following: the effects of a stimulating or depriving environment appear to be most powerful in the early years of childhood; there is evidence that the effects of early intervention programs for children are strengthened by parental involvement; an intensive external supportive environment may contribute to the development of children with disorganized, nonsupportive families; and quality and motivation of staff are directly related to program success. Information was culled from three sources of data--a questionnaire mailed to all California early intervention programs, the Special Education Pupil Count data for 1979-80 and 1980-81, and Preschool Incentive Grant and Infant Preschool Discretionary Grant applications. Findings regarding infant special education programs include that the typical California infant intervention program serves 26 infants with a home/center approach with Designated Instructional Services staff and operates an average of 10.6 months per year. The two greatest needs cited by infant early interventions were for adequate funding and resources to work more effectively with parents. Among results of survey data on prekindergarten intervention programs were that with the possible exception of regional centers, interagency cooperation requires much greater attention and coordination; that assessment and evaluation tend to rely on staff judgment; and the greatest needs were very similar to those for infant programs. Numerous tables with cost data and population statistics are included. (SW)