WorldCat is a union catalog which itemizes the collections of the more than 50,000 libraries which participate in the OCLC global cooperative. It is built and maintained collectively by the participating libraries from more than ninety countries. Created in 1971, it contains more than 1 billion records referencing physical and digital items in more than 360 languages, as of May 2007. It is the world's largest bibliographic database. WorldCat itself is not directly purchased by libraries, but serves as the foundation for many other fee-based OCLC services (such as resource sharing and collection management).

How to access WorldCat

The entire WorldCat database may be searched through the websites of libraries that subscribe to OCLC’s FirstSearch reference service. Often, access to WorldCat requires only an authenticated logon associated with a user’s library account. WorldCat records can also be found on major Web search engines as well as selected bibliographic and bookselling sites, as part of the "Open WorldCat" program (below).

Open WorldCat

In 2003, OCLC began the "Open WorldCat" pilot program, making abbreviated records from a subset of WorldCat available to partner Web sites such as Yahoo!, Google and various booksellers, to increase the accessibility of its member libraries’ collections. On the general search sites, a user can limit their search to Open WorldCat records by adding the phrase "find in a library" (with quotes included) to their search string. In 2004, this functionality became a permanent feature of WorldCat, and the entire database was made available for search-engine harvesting.

Starting in 2005, it is possible to make direct links to Open WorldCat records, allowing immediate access to all libraries holding a given book. Instructions can be found at http://www.oclc.org/worldcat/open/isbnissnlinking/default.htm. The basic structure for linking to items is:

• ISBN: worldcatlibraries.org/isbn/(ISBN)
• ISSN: worldcatlibraries.org/issn/(ISSN number)
• OCLC Number: worldcatlibraries.org/oclc/(OCLC number)

Examples:

• ISBN - The Da Vinci code
• ISSN - Newsweek
• OCLC Number - Dictionary of American naval fighting ships

The easiest way to obtain an OCLC number is to go to a statewide union catalog, like California'sand search for the desired book. The OCLC number will appear towards the bottom of any given record.

Once in an Open WorldCat record, a user is asked to type in his zip code and the nearest libraries that own the book are displayed. If his library is an OCLC member, then available library services will appear on the right hand of the page.

WorldCat.org

In August 2006, it became possible to search WorldCat directly through a central Web page at worldcat.org or through a downloadable search box. Anyone can download the WorldCat search box and add it to a blog or Web site through a WorldCat Affiliate program.

Watch WorldCat grow

As of January 2007, WorldCat has 1.1 billion holdings in its catalog. OCLC has made a Watch WorldCat Grow page that updates every 8 seconds and tells you the bibliographic information for the most recently added entry.

WorldCat Identities

Prototyped as of February 2007, WorldCat Identities provides pages for 20 million 'identities' (predominantly authors and persons who are the subjects of published titles). Several thousand of these pages provide links to Wikipedia biographical pages.

See also

• Open Library

External links

• worldcat.org
• WorldCat home page at oclc.org
• Description of the Open WorldCat program
• Try an Open WorldCat search