Ten papers from a May, 1983 seminar on siblings of mentally retarded and developmentally disabled persons are presented. Participants include parents and siblings, and represent a variety of professions including social work, nursing, and psychology. The following papers are included: "Life with an Older Sister" (S. Miller and H. Kalish); "Raising a Family and Dealing with Differences in Children: A Parent's View" (C. Moore); "Normal Siblings of Retarded Persons" (M. Schreiber); "Siblings' Feelings: A Need for Expression" (M. Neel); "Groups for Normal Siblings of Developmentally Handicapped Children" (T. Mates); "Modification of Sibling Interaction in Families with a Mentally Retarded Child" (J. Vespo); "Explaining Differences to Children (J. Giglio); "A Developmental Perspective of the Siblings of Handicapped Children" (J. Feigon); "A Family Systems Look at the Developmentally Disabled" (M. Jaffe-Ruiz); and "The Parent Perspective" (C. Moore). (CL)