ISBN

International Standard Book Number

File:EAN-13-ISBN-13.svg A 13-digit ISBN, 978-3-16-148410-0, as represented by an EAN-13 bar code
Acronym	ISBN
Organisation	International ISBN Agency
Introduced	1970 (1970)
No. of digits	13 (formerly 10)
Check digit	Weighted sum
Example	978-3-16-148410-0
Website	isbn-international.org

The International Standard Book Number (ISBN) is a numeric commercial book identifier that is intended to be unique.

Occasionally, publishers erroneously assign an ISBN to more than one title—the first edition of The Ultimate Alphabet and The Ultimate Alphabet Workbook have the same ISBN, 0-8050-0076-3. Conversely, books are published with several ISBNs: A German second-language edition of Emil und die Detektive}} has the ISBNs 87-23-90157-8 (Denmark), 0-8219-1069-8 (United States), 91-21-15628-X (Sweden), 0-85048-548-7 (United Kingdom) and 3-12-675495-3 (Germany).  In some cases, books sold only as sets share ISBNs. For example, the Vance Integral Edition used only two ISBNs for 44 books.  Publishers purchase ISBNs from an affiliate of the International ISBN Agency.

An ISBN is assigned to each separate edition and variation (except reprintings) of a publication. For example, an e-book, a paperback and a hardcover edition of the same book will each have a different ISBN. The ISBN is ten digits long if assigned before 2007, and thirteen digits long if assigned on or after 1 January 2007.

EAN format used in barcodes, and upgrading

Currently the barcodes on a book's back cover (or inside a mass-market paperback book's front cover) are EAN-13; they may have a separate barcode encoding five digits called an EAN-5 for the currency and the recommended retail price. For 10-digit ISBNs, the number "978", the Bookland "country code", is prefixed to the ISBN in the barcode data, and the check digit is recalculated according to the EAN-13 formula (modulo 10, 1× and 3× weighting on alternating digits).

Partly because of an expected shortage in certain ISBN categories, the International Organization for Standardization (ISO) decided to migrate to a 13-digit ISBN (ISBN-13). The process began on 1 January 2005 and was planned to conclude on 1 January 2007. As of 2011, all the 13-digit ISBNs began with 978. As the 978 ISBN supply is exhausted, the 979 prefix was introduced. Part of the 979 prefix is reserved for use with the Musicland code for musical scores with an ISMN. The 10-digit ISMN codes differed visually as they began with an "M" letter; the bar code represents the "M" as a zero, and for checksum purposes it counted as a 3. All ISMNs are now thirteen digits commencing 979-0; 979-1 to 979-9 will be used by ISBN.

Publisher identification code numbers are unlikely to be the same in the 978 and 979 ISBNs, likewise, there is no guarantee that language area code numbers will be the same. Moreover, the 10-digit ISBN check digit generally is not the same as the 13-digit ISBN check digit. Because the GTIN-13 is part of the Global Trade Item Number (GTIN) system (that includes the GTIN-14, the GTIN-12, and the GTIN-8), the 13-digit ISBN falls within the 14-digit data field range.

Barcode format compatibility is maintained, because (aside from the group breaks) the ISBN-13 barcode format is identical to the EAN barcode format of existing 10-digit ISBNs. So, migration to an EAN-based system allows booksellers the use of a single numbering system for both books and non-book products that is compatible with existing ISBN based data, with only minimal changes to information technology systems. Hence, many booksellers (e.g., Barnes & Noble) migrated to EAN barcodes as early as March 2005. Although many American and Canadian booksellers were able to read EAN-13 barcodes before 2005, most general retailers could not read them. The upgrading of the UPC barcode system to full EAN-13, in 2005, eased migration to the ISBN-13 in North America.

See also

• ASIN (Amazon Standard Identification Number)
• BICI (Book Item and Component Identifier)
• CODEN (serial publication identifier currently used by libraries; replaced by the ISSN for new works)
• DOI (Digital Object Identifier)
• ESTC (English Short Title Catalogue)
• ISAN (International Standard Audiovisual Number)
• ISMN (International Standard Music Number)
• ISRC (International Standard Recording Code)
• ISSN (International Standard Serial Number)
• ISTC (International Standard Text Code)
• ISWC (International Standard Musical Work Code)
• ISWN (International Standard Wine Number)
• LCCN (Library of Congress Control Number)
• Lebanese ISBN Agency
• License number (East German books) (Book identification system used between 1951 and 1990 in the former GDR)
• List of group-0 ISBN publisher codes
• List of group-1 ISBN publisher codes
• List of ISBN identifier groups
• OCLC number (Online Computer Library Center number)
• Registration authority
• SICI (Serial Item and Contribution Identifier)
• VD 16 (Verzeichnis der im deutschen Sprachbereich erschienenen Drucke des 16. Jahrhunderts, "Bibliography of Books Printed in the German Speaking Countries of the Sixteenth Century")
• VD 17 (Verzeichnis der im deutschen Sprachraum erschienenen Drucke des 17. Jahrhunderts, "Bibliography of Books Printed in the German Speaking Countries of the Seventeenth Century")