Mary Ainsworth's work on the importance maternal sensitivity for the development of infant attachment security is widely recognized as one of the most revolutionary and influential contributions to developmental psychology in the 20th century. Her longitudinal studies of naturalistic mother-infant interactions in Uganda and Baltimore played a pivotal role in the formulation and acceptance of attachment theory as a new paradigm with implications for developmental, personality, social, and clinical psychology. The chapters in this volume collectively reveal not only the origins and depth of her...