Longitudinal research (or observing the same subject across time) in human development requires more careful planning than do cross-sectional studies and is demanding theoretically and organizationally. This volume focuses on methods of data treatment in longitudinal research emphasizing the importance of careful matching of methodology to the substantive problem under consideration. It deals particularly with concepts of stability and change that are central to personality and developmental research. Contributors to this volume explore the methodology and scope of life span studies in a variety of contexts, including intellectual and cognitive development, transitions such as that from childhood to early adult life, social mobility, behavioral genetics, and psychological disorder, particularly depression. It is a valuable reference for a wide range of researchers in developmental psychology, social and behavioral science, psychiatry, epidemiology, and statistics.