Studies on the effects of early day care can be characterized according to two distinct research trends. In the first, which occurred during the 1960s and 1970s, the principal issue was whether day care had any inevitable and negative consequences for the child and, particularly, the mother-child attachment. The second, more recent, trend has been to investigate the individual, family, and institutional conditions that enhance the effects of nonmaternal care. A review of the evidence from these two research trends indicates that: (1) early day care experiences have no long-term effects on intellectual development, except for economically disadvantaged children; (2) some day-care-reared infants display more anxious or avoidant behavior than home-reared infants; (3) for certain children, early day-care experience is associated with heightened interaction with children and lower compliance with adults; and (4) attitudes and family circumstances associated with nonmaternal care, as well as the nature and quality of the caregiving, must be considered when accounting for consequences related to substitute care. These indications raise questions for a number of policy issues, including what policy initiatives deserve consideration. (PCB)