A MECHANIZED CIRCULATION SYSTEM CURRENTLY IN OPERATION AT LEHIGH UNIVERSITY HAS PROVEN TO GIVE RELIABLE CONTROL OF CIRCULATION ALTHOUGH IT HAS NOT SAVED ON OPERATING COSTS. WHEN THE STUDY WAS UNDERTAKEN TO DETERMINE THE FEASIBILITY OF CHANGING FROM THE PREVIOUS MANUAL SYSTEM TO THE CURRENT ONE, THE LIBRARY WAS SERVING A STUDENT BODY OF 4500 STUDENTS AS WELL AS 3000 NON-UNIVERSITY PATRONS AND 275 FULL TIME FACULTY MEMBERS. THE CIRCULATION AT THAT TIME WAS ABOUT 151,000 ITEMS A YEAR AND WAS CREATING PROBLEMS OF CONTROL AND CURRENCY OF INFORMATION. WITH THE NEW SYSTEM, LOANS ARE RECORDED FROM KEYPUNCHED BOOK CARDS AND BORROWERS' IDENTIFICATION BADGES BY MEANS OF AN IBM 357 DATA COLLECTOR TO PRODUCE TRANSACTION RECORDS. DAILY THESE RECORDS ARE USED TO UPDATE IN A GE 225 COMPUTER THE TAPE CIRCULATION RECORD AND TO PRODUCE A NEW PRINTED CIRCULATION RECORD AND A STATISTICAL ANALYSIS OF THE LOAN. OTHER PROCEDURES IN THE SYSTEM PROVIDE FOR AUTOMATIC HANDLING OF OVERDUE AND FINE NOTICES AND FOR MAKING RECALLS FOR BOOKS WANTED BY OTHER PERSONS. BESIDES THE SPECIFIC COST DATA GIVEN THROUGHOUT THE REPORT, EXAMPLES OF AND INFORMATION ABOUT THE SEVERAL PRINTOUTS ARE GIVEN IN THE APPENDICES. (CM)