also runs WorldCat, name of the OCLC Online Union Catalog, which is a
merged electronic catalog of libraries around the world, and probably the
world's largest bibliographic database with its 38 million records (at the
beginning of 1998) in 400 languages (with transliteration for non-Roman
languages), and an annual increase of 2 million bibliographic records.

WorldCat is derived from a concept which is the same for all union catalogs:
earn time to avoid the cataloguing of the same document by many catalogers
worldwide. When they are about to catalog a publication, the catalogers of the
member libraries search the OCLC catalog. If they find the corresponding record,
they copy it in their own catalog and add some local information. If they don't
find the record, they create it in the OCLC catalog, and this new record will
immediately be available to all the catalogers of the member libraries
worldwide.

Unlike RLIN, another international bibliographic database (see below) which
accepts several records for the same document, the OCLC Online Union Catalog
takes into consideration only one record per document, and emphatically requests
its members not to create double records for documents which have already been
cataloged. The records are created in USMARC format (MARC: machine readable
catalog) according to the Anglo-American Cataloguing Rules, 2nd version (AACR2).

What is the history of OCLC? According to the website:

"In 1967, the presidents of the colleges and universities in the state of Ohio
founded the Ohio College Library Center (OCLC) to develop a computerized system
in which the libraries of Ohio academic institutions could share resources and
reduce costs.

OCLC's first offices were in the Main Library on the campus of the Ohio State
University (OSU), and its first computer room was housed in the OSU Research
Center. It was from these academic roots that Frederick G. Kilgour, OCLC's first
president, oversaw the growth of OCLC from a regional computer system for 54
Ohio colleges into an international network. In 1977, the Ohio members of OCLC
adopted changes in the governance structure that enabled libraries outside Ohio
to become members and participate in the election of the Board of Trustees; the
Ohio College Library Center became OCLC, Inc. In 1981, the legal name of the
corporation became OCLC Online Computer Library Center, Inc. Today, OCLC serves
more than 27,000 libraries of all types in the U.S. and 6