Recent research on the father-infant relationship is briefly reviewed. Those studies documenting changes that take place in parent and infant behavior when the mother-infant dyad is transformed into the mother-father-infant triad are judged especially important to advancing the study of early human experience, since they highlight the influence of the marital relationship on the parent-infant relationship. In so doing, these investigations of "second-order effects" in parent-infant interaction document the fact that inclusion of the father in the study of infancy creates a family system comprised of marital and parent-child relations. Serious consideration of this contribution underscores the need for "wedding" the disciplines of family sociology and developmental psychology in their respective concerns for marital and parent-infant relationships. A transactional framework for examining early experience in the family system is proposed to meet this need. It draws specific attention to the fact that parenting affects and is affected by the infant, who both influences and is influenced by the marital relationship, which in turn both affects and is affected by parenting. Evidence from the disciplines of family sociology and developmental psychology is reviewed in terms of this framework to illuminate direct and indirect pathways of influence within the family system during infancy and to stimulate interdisciplinary investigation.Students of early experience have long recognized the significance of the mother-infant relationship, but only recently have they come to study the father-infant relationship. This delay in attention stems in large measure from the psychoanalytic ancestry of developmental psychology, theories of infant-mother attachment derivative of this heritage, and cultural traditions that minimized the significance of the infant's relations with its "second parent."It is significant to note that when students of infancy first began to study father, they traversed the same ground covered years earlier by investigators of mothering: Father This manuscript has benefited greatly from thoughtful reviews provided by Michael Lamb, Alison ClarkeStewart, and Michael Lewis and several anonymous reviewers. I am most indebted, however, to Frank Pedersen. He not only stimulated this work through his own empirical and scholarly efforts, but he has provided generously of his time and energy in helping me to clarify my own thinking.Requests for reprints should be sent to