The Early Training Project, supported by the National Institute of Mental Health experimentally tested a developmental intervention program designed to improve the educability of young educationally deprived children. Three groups were randomized from a group of 65 deprived children born in 1958 in a small southern city. One group had three summers of a specially planned preschool, the other two. Both had the services of a specially trained home visitor during the first grade. The third group served as the local control group. A fourth group in a town similar in economic structure, but 60 miles distant, served as an additional control group. The maximum effect of intervention on intelligence scores was obtained just prior to school entrance. An extended program of pre-school intervention can have lasting effects only if the public school and community cooperatively "capitalize" on such gains. (EM)