The articles provided within this special section of the Journal of Personality Disorders are abbreviated versions of papers presented at the first often international conferences that are intended to enrich the empirical base in preparation for the eventual development of the fifth edition of the American Psychiatric Association's (APA) Diagnostic and Statistical Manual of Mental Disorders. This article provides the historical background for and a brief description of the first conference, which was concerned with the research that would help move the field toward a dimensional classification of personality disorder. (PsycINFO Database Record (c) 2008 APA, all rights reserved) (from the journal abstract)