ADDRESSED TO PUBLIC HEALTH WORKERS AND PHYSICIANS IN GENERAL PRACTICE, THE PAMPHLET INTRODUCES METHODS OF DETECTING AND MANAGING PHENYLKETONURIA, AN INHERITED METABOLIC DISORDER ASSOCIATED WITH MENTAL RETARDATION. INFORMATION, UPDATED FROM THE 1961 EDITION, IS INCLUDED ON THE INCIDENCE AND GENETICS, BIOCHEMISTRY, AND CLINICAL COURSE OF THE DISORDER. SCREENING PROGRAMS FOR NEWBORN INFANTS, MENTALLY RETARDED POPULATIONS, AND OTHER HIGH RISK GROUPS ARE DESCRIBED. LABORATORY PROCEDURES DISCUSSED ARE THE SCREENING AND THE CONFIRMATORY BLOOD TESTS FOR PHENYLALANINE, AND THE FERRIC SALT AND THE DINITROPHENYLHYDRAZINE TEST TUBE URINE TESTS FOR PHENYLPYRUVIC ACID. DIETARY TREATMENT IS CONSIDERED, AND A GENERAL SUMMARY IS GIVEN. A 79-ITEM REFERENCE LIST AND AN EIGHT-ITEM BASIC READING LIST ARE PROVIDED. THREE FIGURES ARE INCLUDED. AN APPENDIX PRESENTS TABLES OF DIETARY INFORMATION AND SAMPLE MENUS. THIS DOCUMENT IS AVAILABLE FROM THE SUPERINTENDENT OF DOCUMENTS, U. S. GOVERNMENT PRINTING OFFICE, WASHINGTON, D. C. 20402, FOR $0.15. (JD)