This article describes the interactions between a highly attuned, sensitive mother, who had the capacity to achieve primary maternal preoccupation, and her infant during his first four months of life. The evolving secure attachment patterns discerned from weekly observations in a naturalistic setting correspond with Beatrice Beebe’s findings using microanalysis of mother-infant face-to-face interactions to predict the nature of the four-month infant’s emerging internal working model of attachment. Using a series of vignettes, the author illustrates how this mother-infant dyad were adept at coordinating their attention, affective responses, vocal rhythms, and touch in ways that seemed to promote feelings of mutual recognition and enjoyment for them both. The mother’s capacity for reflective functioning enabled her to imagine what her baby was feeling and to consistently comfort him, contributing to the formation of their secure mother-infant bond.