Historical changes in the emphasis and focus of Project Head Start from 1965 to the present are briefly reviewed in this paper. Head Start was conceived of as primary prevention designed to enable children from lower income families to obtain educational prerequisites to formal schooling. The early years of the project were also characterized by ideosyncratic implementation and monitoring, an emphasis on the whole child, parent involvement, and uncertain outcomes. In the middle years, Head Start became the nation's laboratory for innovations in curriculum and evaluation in the areas of early learning and development. The project contributed to increased interest in the study of childhood development in the family, and emphasis on the use of observational methods. More recently, Head Start has give more attention to bilingual and bicultural models, and the impact of programs upon children's self-concepts and parental esteem. As yet, however, no profile of early learning and development in the families of prospective Head Start children has been made. In this regard, the future of Head Start lies in how well it can divulge what it has learned and is learning about how children and families positively cope with environmental stress and how the families provide a basis for positive early cognitive and social development. (Author/RH)