xISBN, which began as an OCLC Research project and has been available at no charge for individual, non-commercial use since February 2007, takes its information from WorldCat, the world’s richest database for discovery of items held in libraries. The service helps a user find additional resources when any ISBN assigned to any printing or edition of the work is known. Users submit an ISBN to the service and receive a list of related ISBNs and selected metadata.

ISBNs are related to each other using librarian-cataloged bibliographic records in WorldCat. These WorldCat records have had an algorithm applied that implements the FRBR conceptual model for information objects, which brings multiple versions of a source work together under one record. The FRBR model keeps WorldCat users from having to browse numerous records that represent many different manifestations of a book — such as different printings, hardcover or paperback editions, audiobooks or film versions.

xISBN is ideal for Web-enabled search applications, such as library catalogs and online booksellers. Use xISBN to:

• Help users of an online bookseller first determine if the book is available at their local library.
• Confirm that no alternative versions of a work are available before a library sends an interlibrary loan request.
• Use a single search to check holdings of all editions of a work before making a selection for acquisition.

More information about the xISBN service, including subscription pricing and an order form, is available at the OCLC WorldCat Web site. Please send an e-mail to xisbn-support@oclc.org for additional details about the service.