Important progress in our understanding of the natural course of personality disorders (PDs) is documented in the articles for this special section. This progress could set the stage for ideas developed in the study of PDs to play a central role in research on psychopathology more broadly conceived. The Collaborative Longitudinal Personality Disorders Study (Skodol et al., this issue), the Children in the Community Study (Cohen, Crawford, Johnson, & Kasen, this issue), and the McLean Study of Adult Development (Zanarini, Frankenburg, Hennen, Reich, & Silk, this issue) reveal the importance of personality in understanding psychopathology, and point toward a dimensional approach to conceptualizing psychopathology that could also frame categorical clinical decision making processes.