The findings of several longitudinal studies of low income children who participated in experimental preschool intervention programs over the past decade and a half are summarized in this report. The data resulting from these studies are organized into four categories: (1) preschool effects on target children's later school performances, including retention in grade, significant changes in achievement and intelligence test scores, and assignment to special education classes in the primary grades; (2) attitudes and values of the children and parents involved in the program related to children's achievement motivation and self-esteem and parents' aspirations for their children; (3) kinds of preschool programs that were most effective in helping the target children avoid placement in special education classes; (4) determinants of special education placements. Data showed that the early education programs studied apparently had lasting effects in the following areas: reduced number of target children assigned to special education classes; reduced number of children retained in grade; higher achievement test scores for children at the fourth grade level; higher IQ scores for target children than controls (in three projects); higher achievement oriented attitudes and values. All programs were found to be about equally effective in helping target children avoid special education placement. (SE)