The ISBN is divided into four parts separated by a space or hyphen: a group identifier one to five digits in length identifying the national, language, geographic, or other area in which the edition is published; a publisher prefix one to seven digits in length uniquely identifying the publisher; a title number one to six digits in length identifying the title, volume, or edition of the work; and a check digit that allows any transcription errors in the preceding sequence to be detected by a computer. For example, in the ISBN 0-8389-0847-0, the 0 at the beginning identifies the United States as the country of publication, the second element (8389) identifies the American Library Association as the publisher, the third element (0847) identifies the 2003 edition of the book Metadata Fundamentals for All Librarians by Priscilla Caplan, and the 0 at the end is the check digit. When a calculated check digit is the number 10, the letter X is used, but in the other parts of the ISBN only the arabic numerals 0-9 are used.
The ten-digit ISBN system had a theoretical numbering capacity of one billion. As ISBNs were assigned in over 150 countries, the rate of depletion accelerated, especially with the proliferation of new publishing formats. To increase numbering capacity, ISO introduced a thirteen-digit ISBN on January 1, 2007, identical to the EAN-13 barcode version of the ten-digit ISBN, which has an added three-digit prefix (978- for books) and a recalculated check digit. In the U.S., a five-digit add-on code is used in the publishing industry for price information, the lead digit identifying currency (5 for the U.S. dollar, 6 for the Canadian dollar, 1 for the British pound, and so on). In the United States, allocation of publisher prefixes and assignment of ISBNs is managed by Bowker. ISBN codes for publishers are listed in the Publishers' International ISBN Directory available from Bowker. Click here to learn more about the ISBN. Compare with International Standard Music Number and International Standard Serial Number. See also: Book Item and Contribution Identifier.
Resource Description and Access (RDA) is the successor to the cataloging rules, AACR2. RDA completely revamps the structure of the cataloging instructions by closely following the entity-relationship model used to construct databases.