THIS DOCUMENT IS A COMPANION TO A NONTECHNICAL SUMMARY REPORT. IT IS INTENDED FOR READERS WITH A BACKGROUND IN THE TECHNICAL ASPECTS OF COMPUTER SOFTWARE. THE SYSTEM WAS DEVELOPED TO ENABLE INVESTIGATORS TO USE FACIAL MEASUREMENTS OBTAINED FROM PHOTOGRAPHS OR WITNESS SKETCHES AS PARAMETERS FOR SEARCHING KNOWN-OFFENDER FILES BY COMPUTER. AN ALGORITHM FOR PATTERN RECOGNITION IN SUCH A SYSTEM WAS DEVELOPED AT THE UNIVERSITY OF HOUSTON AND IS THE BASIS FOR THE PROGRAM. A SYSTEM USED BY THE OAKLAND, CALIF, POLICE DEPARTMENT WAS SELECTED AS THE EXISTING SYSTEM MOST CONSISTENT WITH THE OBJECTIVES FOR UHMFS. THE UNIVERSITY OF HOUSTON RESEARCH GROUP MODIFIED THE OAKLAND SYSTEM SOFTWARE TO CORRECT SOME OF ITS DEFICIENCIES (PARTICULARLY ITS INABILITY TO HANDLE MORE THAN ONE QUERY AT A TIME) AND TO ADAPT IT FOR THE PATTERN RECOGNITION ALGORITHM. THE RESULTING SYSTEM IS DESCRIBED IN DETAIL. THE USER'S MANUAL GIVES THE THEORY BEHIND ITS OPERATION, THEN PROVIDES STEP-BY-STEP INSTRUCTIONS FOR ENTERING A QUERY. DATA BASE MAINTENANCE IS EXAMINED AND SPECIAL DESIGN OPERATIONS FOR IMPLEMENTING CONCURRENT MULTITERMINAL OPERATION ARE EXPLAINED. RECORD FORMATS AND SUPPORTING DATA FORMS ARE ILLUSTRATED. A VEHICLE FILE, WHICH IS MAINTAINED CONCURRENTLY WITH THE PHYSICAL PERSONAL DESCRIPTION FILE, IS ALSO EXPLAINED. APPENDED MATERIALS INCLUDE UPDATE FORMATS, FACE PATTERN ILLUSTRATIONS, A DICTIONARY OF SYSTEM CODES, AND SELECTED REFERENCES. FOR A RELATED REPORT, SEE NCJ-47586. (GLR)