Research on the social development of infants has probably been the most influential advance in empirical science for psychoanalysis. The work of Daniel Stern (1985, 1994) and Robert Emde (1997, 1980a, 1980b, 1981, 1988, 1992) established infant research at the center of psychoanalytic theorization. The work reported in this volume has built on the achievement of these and other pioneers of infant research to produce a psychoanalytic model that, we hope, is of relevance to clinicians.