WRITTEN FROM THE STANDPOINT OF THE SOCIOLOGIST OR SOCIAL SCIENTIST, THIS BOOK REPORTS DATA OBTAINED FROM STATISTICAL RESEARCH ON MENTAL RETARDATES. ITS CHIEF PURPOSE IS THE SCIENTIFIC STUDY OF THE MENTALLY RETARDED AND PROVISIONS MADE FOR THEM IN THE UNITED STATES. DISCUSSION OF THE GENERAL CONDITION COVERS DEFINITION AND CLASSIFICATION, ETIOLOGY, TRENDS, INCIDENCE, AND PROPORTIONS BY SEX, BY AGE, BY RACE AND NATIVITY, AS WELL AS PRESENCE OF OTHER DEFECTS, DEATH RATES, MARITAL CONDITION, AND EXTENT OF SCHOOLING. PERTINENT LEGISLATION AND JUDICIAL DECISIONS REGARDING MENTAL DEFECTIVES ARE OUTLINED. INFORMATION ON INSTITUTIONAL PROVISIONS TREATS THE FOLLOWING--HISTORY, CONCEPTIONS, PROVISIONS BY STATES, ORGANIZATION OF INSTITUTIONS, ADMISSIONS AND SEPARATIONS, WORK, COSTS, COUNTY AND CITY INSTITUTIONS, PRIVATE BENEFACTIONS, DAY SCHOOLS, LOCAL TRAINING CENTERS, MENTAL RETARDATES IN HOSPITALS FOR MENTALLY ILL, AND PRIVATE INSTITUTIONS. SOME NON-INSTITUTIONAL PROVISIONS DESCRIBED ARE EMPLOYMENT, SHELTERED WORKSHOPS, COLONIES, PAROLE, PRIVATE OR FOSTER HOMES, PROVISION IN ONE'S OWN HOME, AND PUBLIC PENSION SYSTEMS. A BRIEF ACCOUNT OF VARIOUS ORGANIZATIONS HISTORICALLY CONCERNED WITH MENTAL RETARDATION IS GIVEN. CONCLUSIONS ARE DRAWN ABOUT CHANGING PUBLIC ATTITUDES AND ABOUT WORK OPPORTUNITIES. DATA APPEAR TABULATED IN 16 APPENDIXES. A 54-PAGE BIBLIOGRAPHY CONCLUDES THE STUDY. THIS DOCUMENT IS AVAILABLE FROM THE TYCO SHIPPING SERVICE, INC., 788 BLOOMFIELD AVENUE, CLIFTON, NEW JERSEY 07721, FOR $10.00. (DF)