The American Psychiatric Association's rejection of proposals for radical change in the classification of personality disorders was a result of divisions among researchers studying these diagnoses. This article examines the current state of the field and its prospects, with emphasis on definitions, diagnosis, etiology, prevalence, outcome, and treatment. More definitive conclusions will require a larger body of research than is currently available, including multivariable studies in which biological, psychological, and social factors, as well as their interactions, are examined in the same research design.