This volume initiates a series devoted to theory and research in behavioral pedi­ atrics. Focusing attention on the limited scientific contributions to understanding the development of behavior will, we hope, stimulate further research in this vitally important area of human knowledge. The ability of an individual to achieve his or her full potential as an adult is to a significant degree determined by critical variables in this development within a given society. Study of this aspect of human biology, therefore, may have far-reaching effects on the evolving human species. An awareness of the complexity of the behavioral patterns in infancy is of relatively recent origin and is an obvious essential starting point for this series of publications. The need to discriminate between objective observations and theo­ retical constructs and to design scientifically valid experiments is vital to progress in understanding early infant behavior. It is easy to misinterpret apparent responses to interventions, especially in infants at biological risk. Preterm infants and their caretakers are particularly challenging as subjects but very difficult to assess scientifically. The interactions between mother and newborn and father and newborn hold promise of substantial additional insights into the development of behavior. Thus, this volume provides interesting perspectives into the relationship of the evolving immature neurological system to complex behavior patterns in newborn infants which raise many new questions and exciting opportunities to extend our very limited knowledge about the newborn infant''s psychosocial, emo­ tional, and cognitive development. RICHARD E. BEHRMAN, M. D.