Portions of this paper were presented at a research briefing, sponsored by the Subcommittee on Human Resources of the U.S. House of Representatives Committee on Ways and Means. Results are presented from evaluations of several early intervention programs, all of which provided high quality, center-based early childhood education and family-oriented services. Three perspectives are brought to the topic: (1) the developmental outcomes of children who have been identified as being vulnerable due to environmental circumstances; (2) the processes underlying the links between circumstances such as parental poverty and low education and child well-being; and (3) the efficacy of early childhood intervention programs for altering vulnerable children's success in school and beyond. The first perspective deals with the ways in which children develop that enable them to enter kindergarten with the competencies necessary to do well in school. The second considers the mechanisms that tie environmental conditions such as poverty and low parental education to child well-being. The third stresses the potential for early childhood education programs to alter school trajectories of vulnerable children. Concluding points are summarized for which there is consensus, by developmental researchers and policy experts, given the state of the evidence on the evaluation of early intervention programs. First, high quality center-based programs enhance vulnerable children's school-related achievement and behavior. Second, these effects are strongest for poor children and for children whose parents have little education. Third, these positive benefits continue into the late elementary school and high school years, although effects are smaller than they were at the beginning of elementary school. Fourth, programs that are continued into elementary school and that offer high 'doses' of early intervention have the most sustained long-term effects. It is unrealistic, given our knowledge of development, to expect short-term early interventions to last indefinitely, especially if children end up attending poor quality schools. It is magical thinking to expect that if we intervene in the early years, no further help will be needed by children in the elementary school years and beyond. [This issue of "Social Policy Report" also includes the following commentaries: (1) What We Can Expect From Early Childhood Intervention Programs (Janet Currie); (2) Charting Intervention Effects Over Time (Robert Emde); and (3) Forty Years of Believing In Magic Is Enough (Edward Zigler). Additional support for this issue was provided by the NICHD Research Network on Child and Family Well-Being, Brookings Institution Roundtable on Children and the MacArthur Network on the Economy and the Family.]