Ayres has hc'e'll part-tulle Selllor Resl't1rch Fellozt ill tlle Department of Computillg, University of Bradford, since his retiremellt as Librarian at tlzat utliuersity. Lnrs Nielseii is a Rest'l1rcll Assistant in the Departmellt of Compllting, U111Z~t'1'Sltt/ of Bradforc~; lie was tlle maill programmer o f rhe Bradford OPAC. Mick Rlcllc~t~ is a Sc'llior Compllter Ofticc'r iii the Departmellt of Complltillg, Ulliuerslty of Bradford; lie was s co-ordillator of Projc'et Hc'Ic'lt lIllder the EU Llhrctrle~ Pro~'ralltlllc'. Illlc~cl Torsll Is Professor alld Head of tlrc' Department of Computing, University of Bradford; he has bccll ill(Jolved with the EXLIB allct CANTATE projects of the EU Lihrc~rle~ Pro ylrnnlltle.Reviews the 20 years' evolution and development of the Universal Standard Bibliographic Code (USBC), as a means of overcoming the weaknesses inherent in the International Standard Book Number (ISBN), from its first proposal in 1974. Briefly describes the various phases of USBC's development, including : first extensive testing (1977)(1978)(1979); first research project (1980)(1981)(1982); work performed on USBC as part of proposals for the setting up of the United Kingdom Library Database System (UKLDS) (1982)(1983)(1984), in which USBC was to be used to create a merged retrospective database of MARC and non MARC cataloguing records; the DOCMATCH Projects, using the USBC with periodical articles (1987)(1988)(1989); refining of USBC by means of expert systems (1986)(1987); use of USBC to clean up the BLCMP database (1989)(1990)(1991); and the QUALCAT Project, to set up a large bibliographic database integrating records from different databases and using USBC for merging, cleaning and control and to develop an expert system to select the best record from a number of duplicates (1989)(1990)(1991). Reports briefly on the project, undertaken by Bradford University, Department of Computing, UK, to explore the application of USBC technology to the British Library Document Supply Centre's computerized interloans system. Concludes that, although the USBC has never achieved the status of an accepted standard, it has more than made up for this by demonstrating its adaptability and power in a range of situations requiring an ability to detect duplicate records and to merge and combine files.