Elisabeth M. Dykens, Ph.D., is a child clinical psychologist who has worked with individuals with many different disorders, both clinically and in research. She is particularly interested in the interconnections among genes, brain, and behavior -more specifically, in maladaptive behavior-psychopathology in individuals who have Prader-Willi syndrome, Williams syndrome, or other disorders. Co-author of "Behavior and Development in Fragile X Syndrome" (Sage Publications, 1994), Dr. Dykens has also published numerous studies on the behavior of people with mental retardation. She is a member of the scientific advisory boards of several national syndrome organizations, the steering committee of the National Institute of Child Health and Human Development, the Gatlinburg Society for Research and Theory in Mental Retardation, and the research and evaluation committee for Special Olympics International. Brenda M. Finucane, M.S., is a genetics counselor who serves as Director of Genetic Services at Elwyn Training and Research Institute, one of the United States' oldest multiservice agencies for people with mental retardation. She is the recipient of the 1994 Jane Engelberg Memorial Fellowship from the National Society of Genetics Counselors for her work with women with mental retardation; this work also resulted in her book, "Working with Women with Mental Retardation" (Elwyn Training and Research Institute, 1998). Ms. Finucane is also the author of "What's So Special about Genetics? A Guide for Special Educators" (Elwyn Training and Research Institute, 1996), and "Fragile X Syndrome: A Handbook for Families and Professionals" (National Fragile X Foundation, 1993) and the editor of several parent support group newsletters. She has thus led the way in promulgating etiology-based interventions to parents and educators. Robert M. Hodapp, Ph.D., is a developmental psychologist who has examined how children with different mental retardation syndromes develop and interact with their families. A leading proponent of developmental approaches to children with disabilities, Dr. Hodapp's interests relate to the so-called indirect effects of genetic mental retardation disorders on others, intellectual strengths and weaknesses in Down syndrome, and the possibilities of etiology-based educational interventions. He is the author of "Development and Disabilities: Intellectual, Sensory, and Motor Impairments" (Cambridge University Press, 1998), and co-editor of the "Handbook of Mental Retardation and Development" (Cambridge University Press, 1998). Dr. Hodapp is also a member of the editorial boards of the "American Journal on Mental Retardation" and "Mental Retardation."