This paper focuses on: (1) prevalent assumptions and weaknesses underlying research on preschool programs for 3- to 5-year-olds; (2) issues concerning transition to kindergarten and early elementary grades; (3) the preparation of early childhood personnel; and (4) critical research needs. The review of research findings prompts questions about the advisability of: (1) initiating center- or classroom-based programs for all children regardless of their developmental level or socioeconomic status; (2) the trend toward increased emphasis on academic achievement in the early childhood curriculum in public and private preschools and in early intervention programs for low-income and developmentally delayed children; and (3) leaving unchecked the global enthusiasm for early childhood education as a way of "saving" today's children. The discussion of transition to kindergarten views kindergarten (and perhaps the first three grades) as a developmental transition in the educational process rather than as a discrete curriculum entity. Implications of this view are pointed out. The discussion of the preparation of personnel argues for a systematic plan of personnel development that includes five tiers of activity ranging from in-service training to senior leadership preparation. Four main themes for future research are pointed out. Four figures illustrate, respectively, the delivery modes of the Head Start program, and the parent and child effects of the Center-Based, Home-Based, and Home/School programs. Seventy-eight references are included. (RH)