The articles in this special section provide exciting and useful perspectives on the role of temperament in the development of child and adolescent psychopathology. These articles are valuable both in summarizing what is known and in highlighting issues that must be addressed before further progress can be made. In the future, it will be essential to distinguish between the constructs of temperament and psychopathology in ways that are both scientifically valid and useful to the study of developmental psychopathology. In particular, because existing measures of temperament were not designed to study relations between temperament and psychopathology, new measures are needed that focus on relevant aspects of temperament and are not confounded by the inclusion of items that are close synonyms and antonyms of psychopathology. If circular and mentalistic thinking can be avoided, important advances can be expected from studies of temperament and psychopathology in the context of development.