is a union catalog that itemizes the collections of 17,900
libraries in 123 countries and territories that participate
Online Computer Library Center
Online Computer Library Center
(OCLC) global cooperative. It is
operated by OCLC, Inc. The subscribing member libraries
collectively maintain WorldCat's database, the world's largest
itself available free to
libraries, but the catalog is the foundation for other subscription
services (such as resource sharing and collection management).
is used by the general public and by librarians for
cataloging and research.
3 See also
5 Further reading
6 External links
OCLC was founded in 1967 under the leadership of Fred
Kilgour. That same year,
OCLC began to develop the union
catalog technology that would later evolve into WorldCat; the first
catalog records were added in 1971.
OCLC began the "Open WorldCat" pilot program, making
abbreviated records from a subset of
WorldCat available to partner web
sites and booksellers, to increase the accessibility of its
subscribing member libraries' collections.
In October 2005, the
OCLC technical staff began a wiki project, WikiD,
allowing readers to add commentary and structured-field information
associated with any
WorldCat record. WikiD was later
phased out, although
WorldCat later incorporated user-generated
content in other ways.
In 2006, it became possible for anyone to search
WorldCat directly at
its open website, not only through the subscription
FirstSearch interface where it had been available on the web to
subscribing libraries for more than a decade before.
Options for more sophisticated searches of
WorldCat have remained
available through the FirstSearch interface.
WorldCat Identities began providing pages for 20 million
"identities", which are metadata about names—predominantly authors
and persons who are the subjects of published titles.
As of May 2019,
WorldCat contained over 450 million bibliographic
records in 484 languages, representing over 2.8 billion physical and
digital library assets, and the
WorldCat persons dataset
(mined from WorldCat) included over 100 million people.
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WorldCat contains records in MAchine Readable Cataloging (MARC) format
contributed by library catalogers worldwide who use
OCLC as a
cataloging tool, and these MARC format records can also be downloaded
into other libraries' local catalog systems. This allows libraries to
find and download records for materials they are adding to their local
catalog, without having to undergo the lengthy process of creating a
new catalog entry from scratch for each new item.
WorldCat operates on a batch processing model rather than a real-time
model. That is,
WorldCat records are synchronized at intermittent
intervals with the underlying library catalogs instead of real-time or
every day. Consequently:
WorldCat shows that a particular item is owned by a particular library
but does not provide that library's call number.
WorldCat does not indicate whether an item is currently borrowed,
lost, undergoing restoration or repair, or moved to storage not
directly accessible to patrons (thereby forcing interested patrons to
submit a retrieval request and wait).
WorldCat does not show whether a library owns multiple
copies of a particular title.
As an alternative,
WorldCat allows participating institutions to add
direct links from
WorldCat to their own catalog entries for a
particular item, which enables the user to determine its real-time
status. However, this still requires users to open
multiple Web pages, each pointing to a different online public access
catalog with its own distinctive user interface design (which places
item status in a different portion of the Web browser display), until
they can locate a catalog entry that shows the item is currently
available at a particular library.
Library contributions to
WorldCat are made via the Connexion computer
program, which was introduced in 2001; its predecessor,
was phased out in May 2005.
Faceted Application of Subject Terminology (FAST)
Library and Archives Canada
Research Libraries UK
^ "Search for library items". WorldCat. Online Computer Library
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^ "Worldcat.org Traffic, Demographics and Competitors – Alexa".
www.alexa.com. Retrieved February 4, 2019.
^ 1998 is the date of registry of the WorldCat.org domain; see:
"WorldCat.org WHOIS, DNS, & Domain Info – DomainTools". WHOIS.
Retrieved January 21, 2017. However, the union catalog that became
WorldCat was started three decades earlier, and it was already
available on the web to subscriber libraries at OCLC.org several years
before WorldCat.org was a registered domain name; see: "OCLC.org
WHOIS, DNS, & Domain Info – DomainTools". WHOIS. Retrieved June
^ "About OCLC". Online Computer
Library Center. Retrieved August 18,
^ a b "Inside WorldCat". OCLC. OCLC, Inc. Retrieved August 19, 2019.
^ a b
Margalit Fox (August 2, 2006). "Frederick G. Kilgour, Innovative
Librarian, Dies at 92". The New York Times. Retrieved December 22,
2009. Frederick G. Kilgour, a distinguished librarian who nearly 40
years ago transformed a consortium of Ohio libraries into what is now
the largest library cooperative in the world, making the catalogs of
thousands of libraries around the globe instantly accessible to
far-flung patrons, died on Monday in Chapel Hill, N.C. He was 92.
^ "A brief history of WorldCat". oclc.org. February 10, 2015.
Retrieved February 13, 2014.
^ O'Neill, Nancy (November–December 2004). "Open
WorldCat Pilot: A
User's Perspective". Searcher. 12 (10): 54–60. ISSN 1070-4795.
^ Quint, Barbara (October 27, 2003). "
OCLC project opens WorldCat
records to Google". infotoday.com. Information Today. Retrieved June
^ "WikiD". OCLC. Retrieved March 5, 2015.
^ Storey, Tom (September 2007). "A
WorldCat community: using
WorldCat.org to build a social network of the world's library users"
OCLC (7): 16–17. ISSN 1559-0011. Retrieved
June 26, 2019. Online ratings, tags, reviews, recommendations, lists,
rankings, personal profiles—the social media revolution is here. It
seems the world has exploded with Web 2.0, social networking tools and
^ Bertot, John Carlo; Berube, Katy; Devereaux, Peter; Dhakal, Kerry;
Powers, Stephen; Ray, Jennie (April 2012). "Assessing the usability of
WorldCat Local: findings and considerations". The
82 (2): 207–221. doi:10.1086/664588. JSTOR 10.1086/664588.
Breeding  also makes the following observations about the benefits
of the search system: the presence of a more visually appealing
interface; the grouping of related material; faceted navigation; and
the capability for user-generated content (e.g., reviews). Eden 
also refers to the advantages of user-generated content possible in
^ a b Hane, Paula J. (July 17, 2006). "
OCLC to open
to the world". infotoday.com. Information Today. Retrieved June 26,
^ Prucha, Francis Paul (1994). "National online library catalogs".
Handbook for research in American history: a guide to bibliographies
and other reference works (2nd ed.). Lincoln: University of Nebraska
Press. pp. 25–27. ISBN 0803237014. OCLC 28018047.
Online Computer Library Center
Online Computer Library Center has developed two new programs. One is
called EPIC, a new command-driven full online service with
sophisticated searching features, including subject searches, intended
for librarians and other experienced users. The other, designed for
end-users, is FirstSearch, which contains the database materials found
in EPIC or subsets of them but has a menu interface that
nonspecialists find easy to use. Both EPIC and FirstSearch make
available the full
OCLC Online Union Catalog (called
FirstSearch), but they also function as online database services,
offering their users a wide array of other databases.
^ Hickey, Thomas B. (April 15, 2007). "
WorldCat Identities: Another
View of the Catalog" (PDF). NextSpace.
OCLC (6): 18–19.
ISSN 1559-0011. Retrieved January 18, 2016.
^ "Data strategy [WorldCat]". oclc.org. Retrieved February 11,
^ "What is WorldCat?". worldcat.org. Retrieved February 13, 2015.
^ Dean, Becky (March 3, 2005). "
OCLC Authorities migration timeline".
firstname.lastname@example.org (Mailing list). Retrieved June 26, 2019.
Blackman, Cathy; Moore, Erica Rae; Seikel, Michele; Smith, Mandi (July
WorldCat and SkyRiver: a comparison of record quantity and
Library Resources & Technical Services. 58 (3):
Breeding, Marshall (May 2015). "
Library services platforms: a maturing
genre of products".
Library Technology Reports. 51 (4): 1–38.
Matthews, Joseph R. (July 2016). "An environmental scan of OCLC
alternatives: a management perspective". Public
Library Quarterly. 35
(3): 175–187. doi:10.1080/01616846.2016.1210440.
McKenzie, Elizabeth (January 2012).
OCLC changes its rules for use of
records in WorldCat: library community pushback through blogs and
cultures of resistance (Technical report). Boston: Suffolk University
Law School. Research paper 12-06.
OCLC online union catalog means to me: a collection of
essays. Dublin, Ohio: OCLC. 1997. ISBN 1556532237.
Wilson, Kristen (August 2016). "The knowledge base at the center of
Library Technology Reports. 52 (6): 1–35.
WorldCat data licensing" (PDF). oclc.org. Retrieved December 31,
2018. See also: "Data licenses & attribution". oclc.org. Retrieved
December 31, 2018. Information about licensing of
WorldCat records and
Official website (Mobile)
"WorldCat". oclc.org. Retrieved December 31, 2018. Information on the
OCLC website about WorldCat.
"Bibliographic Formats and Standards". oclc.org. Retrieved December
WorldCat Identities". worldcat.org. Retrieved December 31, 2018.
WorldCat Identities (via