Presented in this paper are a selective review and summary of recent research findings concerning the adult's role in infant development. After an introduction setting forth assumptions guiding the selection of issues and findings, the first section discusses research on parent/infant interaction. Some of the classic concepts of infant development, such as bonding and fear of strangers, are critically examined. Also discussed in the first section are the early relationship between parents and their infant, early forms of self-regulation, interaction at a distance, the beginnings of infant initiative, coping with an expanding awareness and new emotions, and the beginnings of self-assertion. The second section examines the role of nonfamilial caregivers, specifically in relation to group care contexts and their impact on the infant and on the parent-infant relationship. Specific attention is given to the effects of day care on cognitive development and the role of other children in group care settings. The third section considers issues related to lasting effects of the infant's early experience with adults. Discussion focuses on infants at risk, effects of the physical environment, and the need for improved research. Finally, several conclusions based on the reviewed findings are offered. (RH)