This collection brings together work in an important area that has become the focus of major research in European developmental psychology: the longitudinal study of the interaction of cognition and emotion in individual development. Leading international researchers in developmental psychology have prepared chapters that examine transition mechanisms in areas including cognitive and memory development, language development, social and emotional development, and motor development in children. The volume is an outgrowth of a workshop on longitudinal research in individual development, sponsored by the European Science Foundation. It reflects the many conceptual and methodological advances that have taken place in the application of longitudinal strategies to research in developmental psychology, and demonstrates the need for the longitudinal perspective in future research.