Four papers discuss the Harvard Preschool Project whose goal is to learn how to structure the experiences of the first six years of life to encourage maximal development of human competence. To determine what competence at age 6 is, a group of 13 highly competent 6-year-olds of mixed residence, class, and ethnicity were compared to a like group of 13 low competence 6-year-olds and the resultant information was collected in protocols. From this material, a list of differentiating abilities, some social and some nonsocial, was compiled. Highly competent 3-year-olds were found to be more advanced in these abilities than 6-year-olds who were doing poorly. As there was little competence divergence at age one, it was clear that an investigation of the interaction of experience and the development of competence should be focused on the second and third years of life, (mostly familial experiences). To measure comparative experiential histories, an instrument was developed for codification of moment-to-moment behavior on the basis of inferred purpose. The next step will be the collection and analysis of data from families that have succeeded or failed to develop children of high competence. Also planned are longitudinal studies in which children will follow task sequences designed for optimal development. (MH)