The Minnesota Study of Risk and Adaptation was initiated in the mid-1970s as a short-term longitudinal study of infants at elevated risk for abuse and neglect. At the outset, the project leaders intended to characterize the infant, the caregiving environment, and the larger social milieu of the family in as comprehensive a manner as possible so as to test explicitly posed hypotheses about pathways leading from the child, the caregiving environment, and the social milieu to abuse or neglect. Paradoxically, only a minority of infants recruited to the study were ultimately abused or neglected over the 36-month period for which funding had been provided, but it proved possible to identify several antecedent indicators that predicted their outcome. It was also evident from the data that developmental casualty was elevated in this sample and the frequencies of suboptimal outcomes in social, emotional, and behavioral domains were greater than expected for less stressed samples. The study had yielded a wealth of information about infants and families from this at-risk sample and it was clear that the sample must be followed into childhood so as to describe the trajectories of developmental successes and casualties that were already apparent in the first 24 months of data. Alan Sroufe joined the project leaders in this endeavor and the childhood data supported the study of the sample into adolescence and now into adulthood. At this point, children of the original sample of infants are now being assessed using many of the protocols and procedures used with their parents. The study has produced hundreds of published reports about risk and its consequences, as well as about positive adjustment to life in a socio-cultural milieu that frequently can be non-supportive or even dangerous. This essay is a reflection on some accomplishments of the Minnesota study as these have helped shape how developmental scientists think about social and emotional development and more generally about how theory has guided the conceptual, empirical, and measurement plans for the study from its beginning.