The American Psychiatric Association is sponsoring a series of international conferences to set a research agenda for the development of the next edition of the diagnostic manual. The first conference in this series, "Dimensional Models of Personality Disorder: Etiology, Pathology, Phenomenology, and Treatment," was devoted to reviewing the existing research and setting a future research agenda that would be most effective in leading the field toward a dimensional classification of personality disorder. The purpose of this article, authored by the Steering Committee of this conference, was to provide a summary of the conference papers and their recommendations for research. Covered herein are the reviews and recommendations concerning alternative dimensional models of personality disorder, behavioral genetics and gene mapping, neurobiological mechanisms, childhood antecedents, cross-cultural issues, Axes I and II continuity, coverage and cutoff points for diagnosis, and clinical utility.