This volume provides the most in-depth, authoritative resource available on the diagnosis, assessment, etiology, and treatment of gender identity disorder in children and adolescents. The extant literature is integrated with findings from the authors' own clinical research, which incorporates the largest sample of children with gender identity disorder ever studied. Included is information on the disorder's core phenomenology, epidemiology, diagnosis and assessment, associated psychopathology, treatment, and long-term follow-up. Detailed clinical case material is presented throughout.