On any given day in the United States (and probably elsewhere), hundreds of thousands of individuals make visits to physicians with complaints unexplained by physical disease. The history of attempts to understand, classify, and minister to patients with poorly understood physical complaints ranges over a period of at least 2,000 years. There is perhaps no more controversial, ever-shifting classification of psychiatric disorders than that of the somatoform group (to which the editors of this book have added factitious disorders because, as they argue, all medically unexplained symptoms occupy points on a continuum not readily differentiated). At times, classification may appear more a matter of convenience than based on good clinical rationale. Do they belong with adjustment disorders, dissociative disorders, obsessive-compulsive disorder, depression, or other disorders?