Ami Klin, PhD, is the Harris Associate Professor of Child Psychology and Psychiatry at Yale University's Child Study Center. Dr. Klin is the author of more than 60 articles and chapters in the field of autism and related disorders, and has coordinated a series of federally funded research studies focused on Asperger syndrome. His main research interests involve the neuropsychology and social cognition of disorders of socialization. Fred R. Volkmar, MD, is Professor of Child Psychiatry, Psychology, and Pediatrics at Yale University's Child Study Center. Dr. Volkmar is the author of more than 150 articles, chapters, and books in the field of autism and related disorders. He is an editor of the second edition of theHandbook of Autism, chair of the American Academy of Child and Adolescent Psychiatry's committee on autism, and an associate editor of theJournal of Autism and Developmental Disordersand theJournal of Child Psychology and Psychiatry. Sara S. Sparrow, PhD, is Professor of Psychology and Chief Psychologist at Yale University's Child Study Center. Dr. Sparrow is the author of more than 100 articles and chapters in the fields of psychological assessment and developmental disabilities, and the senior author of one of the most widely used psychological instruments, the Vineland Adaptive Behavior Scales. Her main research interests involve the assessment of adaptive behavior, child neuropsychology, and developmental disabilities.