This special issue is concerned with the systematic transformation of persons and personalities as they move through their lives. The focus is on developmental processes early in the life course that influence both long-term stability and change. Contributors represent diverse topics and viewpoints, but offer new data on classical issues of personality, including trait structure, self-regulation and internalization, self-evaluation, and self-efficacy. In addition, the issue includes empirical contributions on newer approaches to bullying, developmental processes in psychopathology, the influence of racial and ethnic discrimination on subsequent adjustment, and cultural influences on personality development. The issue also includes a special contribution addressing methodological and statistical advances in dealing with prospective longitudinal data assessing personality over time.