Changing ideas about the role of early education increasingly point toward universal preschool education for all children. Early education has come to serve many purposes but, as it expands, there is danger that the particular needs of young children will be overlooked by both professionals and parents. This essay underlines the vulnerability of young children and calls attention to the lifelong consequences of preschool experiences. Examining issues concerning the long term effects of preschool experiences, the discussion suggests that the value of early education will vary as a function of a matrix of factors including program quality, the vulnerability of individual children, and family needs. Additionally, the achievements and limitations of evaluation research are described within the context of possible deleterious effects of preschool education. Emphasis is given to the importance of developing ideographic methods of study to achieve more valid assessments of children's response to early education. It is suggested that more time be devoted to understanding the effects of substitute child care on parental attitudes and behavior and to delineating and documenting the damaging consequences of poorly run early childhood programs. (RH)