The five-year process of preparing for the revision of the Diagnostic and Statistical Manual (DSM) has been organized around a series of conferences convened by the American Psychiatric Association, in collaboration with the World Health Organization and the U.S. National Institutes of Health, to address the future of psychiatric diagnosis. Obsessive-Compulsive Spectrum Disorders: Refining the Research Agenda for DSM-V is the fruit of one of those conferences and presents the most academically sound, thought-provoking, and timely papers from the proceedings. As the conference and book demonstrate, recent advances in psychiatric diagnosis suggest a new approach to obsessive-compulsive disorder (OCD) classification: • Research into the pathogenesis of OCD increasingly supports reclassification out of the anxiety disorders and into a separate group of obsessive-compulsive-related disorders (OCRDs). • The relationships among OCRDs may be better defined, delineated, and understood if the current categorical diagnostic approach is supplemented with a dimensional approach which assesses obsessive-compulsive symptom domains.• Obsessive-compulsive disorders are believed to be underdiagnosed in patients who complain of broad symptoms of anxiety, and reclassification of OCD as an OCRD would promote more careful examination of distinct obsessive-compulsive symptoms, yield more accurate diagnosis, and result in more effective treatments.• Reclassification may facilitate future research directions in examining the biological underpinnings of these disorders. In addition to examining the genetic, neurological, and ethno-cultural bases for OCRDs, the book gives special attention to disorders that cross current diagnostic categories, including: • Body dysmorphic disorder (BDD)• Tourettes syndrome and trichotillomania• Impulse-control disorders The process leading to publication of DSM-V is by its nature an exhaustive and complex one, and the conferences play a critical role in reviewing relevant research, assessing the status of scientific knowledge, and advancing that knowledge base. Obsessive-Compulsive Spectrum Disorders: Refining the Research Agenda for DSM-V represents the cutting-edge thinking that will culminate in new diagnoses, classifications, and standards of practice for this debilitating set of disorders. Clinicians and academicians will be fascinated by this glimpse into the next generation of the DSM-V.