Last updated

WorldCat logo.svg
WorldCat homepage.png
WorldCat homepage as of June 2019
Type of site
Network of library content and services
Available in13 languages [1]
List of languages
  • Chinese (Simplified)
  • Chinese (Traditional)
  • Czech
  • Dutch
  • English
  • French
  • German
  • Italian
  • Korean
  • Japanese
  • Portuguese
  • Spanish
  • Thai
  • Urdu
Owner OCLC
URL OOjs UI icon edit-ltr-progressive.svg
RegistrationOptional, but some features require registration (such as writing reviews and making lists or bibliographies)
LaunchedJanuary 21, 1998;25 years ago (1998-01-21) (date of registry of the new domain name; the database already existed since 1971) [2]
Current statusOnline
Content license
Copyright policy
OCLC  number 756372754

WorldCat is a union catalog that itemizes the collections of tens of thousands of institutions (mostly libraries), in many countries, that are current or past members of the OCLC global cooperative. [3] It is operated by OCLC, Inc. [4] Many of the OCLC member libraries collectively maintain WorldCat's database, the world's largest bibliographic database. [5] The database includes other information sources in addition to member library collections. [6] OCLC makes WorldCat itself available free to libraries, but the catalog is the foundation for other subscription OCLC services (such as resource sharing and collection management). WorldCat is used by librarians for cataloging and research and by the general public.


As of December 2021, WorldCat contained over 540 million bibliographic records in 483 languages, representing over 3 billion physical and digital library assets, [4] and the WorldCat persons dataset (mined from WorldCat) included over 100 million people. [7]


OCLC was founded in 1967 under the leadership of Fred Kilgour. [8] 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. [8] [9]

In 2003, 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. [10] [11]

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. [12] WikiD was later phased out, although WorldCat later incorporated user-generated content in other ways. [13] [14]

In 2006, it became possible for anyone to search WorldCat directly at its open website, [15] not only through the subscription FirstSearch interface where it had been available on the web to subscribing libraries for more than a decade before. [16] Options for more sophisticated searches of WorldCat have remained available through the FirstSearch interface. [15]

In 2007, 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. [17]

In 2017, OCLC's WorldCat Search API was integrated into the cite tool of Wikipedia's VisualEditor, allowing Wikipedia editors to cite sources from WorldCat easily. [18] [19]

Beginning in 2017, OCLC and the Internet Archive have collaborated to make the Internet Archive's records of digitized books available in WorldCat. [20]

In May 2022, OCLC announced WorldCat Entities, a new infrastructure for library linked data. [21] [22] Maintenance of WorldCat Identities was suspended and the service will be discontinued as it is being replaced by WorldCat Entities. [23]

In August 2022, OCLC launched a "redesigned and reimagined" website with the stated goal "to offer greater accessibility to the collections". [24] The website now requires the use of JavaScript and is therefore no longer accessible for users of older web browsers or those that have JavaScript disabled for security reasons. The update also removed users' book reviews and replaced them with reviews from Amazon subsidiary GoodReads. [25]

System architecture

Local catalogs of many OCLC member libraries are intermittently synchronized with the WorldCat database. [26] WorldCat allows participating institutions to add direct links from WorldCat to their own local catalog entries for particular items, which enables the user to click through to the local catalog to quickly determine an item's real-time status (for example, whether or not it is checked out). [27]

In a small percentage of libraries, [28] the local catalog is also run by OCLC using an integrated library system called WorldCat Discovery and WorldShare Management Services. [29]

Library contributions to WorldCat are made via the Connexion computer program, [30] which was introduced in 2001; its predecessor, OCLC Passport, was phased out in May 2005. [31] Cataloging librarians may also use the WorldShare Record Manager [32] or WorldCat Metadata API [33] for similar purposes. [34]

See also

Related Research Articles

<span class="mw-page-title-main">Library catalog</span> Register of bibliographic items

A library catalog is a register of all bibliographic items found in a library or group of libraries, such as a network of libraries at several locations. A catalog for a group of libraries is also called a union catalog. A bibliographic item can be any information entity that is considered library material, or a group of library materials, or linked from the catalog as far as it is relevant to the catalog and to the users (patrons) of the library.

<span class="mw-page-title-main">Glossary of library and information science</span>

This page is a glossary of library and information science.

<span class="mw-page-title-main">Librarian</span> Profession

A librarian is a person who works professionally in a library providing access to information, and sometimes social or technical programming, or instruction on information literacy to users.

A discovery system is a bibliographic search system based on search engine technology. It is part of the concept of Library 2.0 and is intended to supplement or even replace the existing OPAC catalogs. These systems emerged in the late 2000s in response to user desire for a more convenient search option similar to that of internet search engine. The results from searching a discovery system may include books and other print materials from the library's catalog, electronic resources such as e-journals or videos, and items stored in other libraries.

<span class="mw-page-title-main">OCLC</span> Global library cooperative (1967–)

OCLC, Inc., doing business as OCLC, is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It was founded in 1967 as the Ohio College Library Center, then became the Online Computer Library Center as it expanded. In 2017, the name was formally changed to OCLC, Inc. OCLC and thousands of its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog in the world. OCLC is funded mainly by the fees that libraries pay for the many different services it offers. OCLC also maintains the Dewey Decimal Classification system.

FamilySearch is a nonprofit organization and website offering genealogical records, education, and software. It is operated by The Church of Jesus Christ of Latter-day Saints, and is closely connected with the church's Family History Department. The Family History Department was originally established in 1894, as the Genealogical Society of Utah (GSU); it is the largest genealogy organization in the world.

The Research Libraries Group (RLG) was a U.S.-based library consortium that existed from 1974 until its merger with the OCLC library consortium in 2006. RLG developed the Eureka interlibrary search engine, the RedLightGreen database of bibliographic descriptions, and ArchiveGrid, a database containing descriptions of archival collections. It also developed a framework known as the "RLG Conspectus" for evaluating research library collections, which evolved into a set of descriptors used in library collection policy statements, last updated in 1997. The Library of Congress used the conspectus in 2015 in the revision of its own collection policy statement, and decided to retain this resource on its website, as a helpful scale for judging an academic collection's depth.

Functional Requirements for Bibliographic Records is a conceptual entity–relationship model developed by the International Federation of Library Associations and Institutions (IFLA) that relates user tasks of retrieval and access in online library catalogues and bibliographic databases from a user’s perspective. It represents a more holistic approach to retrieval and access as the relationships between the entities provide links to navigate through the hierarchy of relationships. The model is significant because it is separate from specific cataloguing standards such as Anglo-American Cataloguing Rules (AACR), Resource Description and Access (RDA) and International Standard Bibliographic Description (ISBD).

<span class="mw-page-title-main">Cataloging (library science)</span> Process of creating meta-data for information resources to include in a catalog database

In library and information science, cataloging (US) or cataloguing (UK) is the process of creating metadata representing information resources, such as books, sound recordings, moving images, etc. Cataloging provides information such as author's names, titles, and subject terms that describe resources, typically through the creation of bibliographic records. The records serve as surrogates for the stored information resources. Since the 1970s these metadata are in machine-readable form and are indexed by information retrieval tools, such as bibliographic databases or search engines. While typically the cataloging process results in the production of library catalogs, it also produces other types of discovery tools for documents and collections.

<span class="mw-page-title-main">Outline of library and information science</span> Overview of and topical guide to library science

The following outline is provided as an overview of and topical guide to library and information science:

WHOIS is a query and response protocol that is used for querying databases that store an Internet resource's registered users or assignees. These resources include domain names, IP address blocks and autonomous systems, but it is also used for a wider range of other information. The protocol stores and delivers database content in a human-readable format. The current iteration of the WHOIS protocol was drafted by the Internet Society, and is documented in RFC 3912.

Serials Solutions was a division of ProQuest that provided e-resource access and management services (ERAMS) to libraries. These products enabled librarians to more easily manage electronic resources that serve the needs of their users. Serials Solutions became part of ProQuest Workflow Solutions in 2011 and the "Serials Solutions" name was retired in 2014. In 2015, Proquest acquired Ex Libris Group, a library automation company with many similar products to those of ProQuest Workflow Solutions. The Workflow Solutions division was to be merged with Ex Libris into a new business group called "Ex Libris, a ProQuest Company".

<span class="mw-page-title-main">Fred Kilgour</span> American librarian (1914–2006)

Frederick Gridley Kilgour was an American librarian and educator known as the founding director of OCLC, an international computer library network and database. He was its president and executive director from 1967 to 1980.

Library technical services are the ongoing maintenance activities of a library's collection, including the three broad areas of collection development, cataloging, and processing. Technical services are the infrastructure that enable the user's experience of many library services and are typically performed "behind the scenes."

A union catalog is a combined library catalog describing the collections of a number of libraries. Union catalogs have been created in a range of media, including book format, microform, cards and more recently, networked electronic databases. Print union catalogs are typically arranged by title, author or subject ; electronic versions typically support keyword and Boolean queries. Union catalogs are useful to librarians, as they assist in locating and requesting materials from other libraries through interlibrary loan service. They also allow researchers to search through collections to which they would not otherwise have access, such as manuscript collections.

Faceted search augments lexical search with a faceted navigation system, allowing users to narrow results by applying filters based on a faceted classification of the items. It is a parametric search technique. A faceted classification system classifies each information element along multiple explicit dimensions, facets, enabling the classifications to be accessed and ordered in multiple ways rather than in a single, pre-determined, taxonomic order.

LibX was a free, open-source scholars' extension for the Internet Explorer browser that lets people use services offered by their library. Users can search their library catalog(s) and databases through a search bar or through a context menu. The context menu is adaptive and configurable. LibX supports the catalogs of all major vendors. In addition, any resource that can be searched using an http GET request can be included, similar to Firefox's smart keywords.

<span class="mw-page-title-main">International Standard Name Identifier</span> 16 digit identifier for people and organisations

The International Standard Name Identifier (ISNI) is an identifier system for uniquely identifying the public identities of contributors to media content such as books, television programmes, and newspaper articles. Such an identifier consists of 16 digits. It can optionally be displayed as divided into four blocks.

<span class="mw-page-title-main">Metadata</span> Data about data

Metadata is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including:

<span class="mw-page-title-main">Trove</span> Australian online library database aggregator

Trove is an Australian online library database owned by the National Library of Australia in which it holds partnerships with source providers National and State Libraries Australia, an aggregator and service which includes full text documents, digital images, bibliographic and holdings data of items which are not available digitally, and a free faceted-search engine as a discovery tool.


  1. "Search for library items". WorldCat. OCLC. Archived from the original on September 22, 2007. Retrieved March 29, 2017.
  2. 1998 is the date of registry of the domain; see: " WHOIS, DNS, & Domain Info – DomainTools". WHOIS . Archived from the original on June 20, 2019. 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 several years before was a registered domain name; see: " WHOIS, DNS, & Domain Info – DomainTools". WHOIS . Archived from the original on June 26, 2019. Retrieved June 26, 2019.
  3. The 2012–2013 OCLC Annual Report noted that the number of "participating libraries (includes active and inactive symbols)" was 78,985: 2012–2013 OCLC Annual Report (Report). p. 5. OCLC   1226313226 . Retrieved March 10, 2022.
  4. 1 2 "Inside WorldCat". OCLC. Archived from the original on January 30, 2017. Retrieved June 19, 2021.
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  8. 1 2 Margalit Fox (August 2, 2006). "Frederick G. Kilgour, Innovative Librarian, Dies at 92". The New York Times . Archived from the original on April 25, 2009. 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.
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  15. 1 2 Hane, Paula J. (July 17, 2006). "OCLC to open WorldCat searching to the world". Information Today. Archived from the original on May 10, 2020. Retrieved June 26, 2019.
  16. 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 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 WorldCat in FirstSearch), but they also function as online database services, offering their users a wide array of other databases.
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  23. "WorldCat Identities". OCLC. March 9, 2023. Archived from the original on March 25, 2023. Retrieved March 15, 2023. The research prototype application is no longer supported or maintained ... We have taken the findings of the research effort and used them to start to build the WorldCat Entities data. These new Entities and their persistent URIs will serve as the foundation for future linked data services similar to those explored in the Identities Research work.
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Further reading