is a union catalog
which itemizes the collections of more than 10,000 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 90 million different records pointing to over 1.2 billion physical and digital assets in more than 360 languages, as of November 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).
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!
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)
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.
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 November 2007, WorldCat has 1.2 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.
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.