ESSENTIAL INFORMATION IS PRESENTED TO SOCIAL WORKERS SO THAT THEY MAY PROVIDE BETTER SERVICES TO MENTALLY RETARDED CHILDREN AND THEIR FAMILIES. INCLUDED ARE (1) A LOOK AT THE PAST, CURRENT DEFINITION, AND DISCUSSION OF CAUSATION, (2) FACTORS IN DEVELOPMENT, GROWTH AND BEHAVIORAL CHARACTERISTICS FOR THREE LEVELS OF RETARDATION, AND (3) SEVERAL FAMILY RELATED PROBLEMS AND FACTORS IN FAMILY ADJUSTMENT. CASEWORK AND SOCIAL GROUP WORK WITH PARENTS AND WITH CHILDREN ARE ALSO DISCUSSED. THE FOLLOWING TOPICS ABOUT PLANNING ARE TREATED--HOME CARE, INSTITUTIONAL CARE, FOSTER HOME CARE, SMALL GROUP HOMES, ADOPTION, SUPPLEMENTING PARENTAL CARE WITH DAY CARE OR HOMEMAKER SERVICES, OTHER SERVICES, AND COMMUNITY PLANNING. A 65-ITEM REFERENCE LIST IS INCLUDED. THIS DOCUMENT WAS PUBLISHED BY THE SUPERINTENDENT OF DOCUMENTS, U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON, D.C. 20402, AND IS AVAILABLE FOR $0.45. (DF)