Empirical infant research exists as a fi eld entirely separate from adult treatment. However, the fi ndings have contributed greatly to our understanding of the nature of communication and of attachment in adult treatment. Beginning in the 1970s with the seminal work of Lou Sander (1977) and Dan Stern ( 1985 ), gradually a group including Joe Lichtenberg, Ed Tronick, Karlen Lyons-Ruth, Beatrice Beebe, and Frank Lachmann saw that these fi ndings could reshape psychoanalytic developmental theory and the theory of therapeutic action in adult treatment. Some of these theorists operated in the domain of face-to-face mother-infant communication, some in the domain of attachment research, some in adult treatment, and some in the fi elds of infant research and adult treatment.