International Standard Book Number (ISBN)

The International Standard Book Number, commonly abbreviated as ISBN, is a unique numerical identifier assigned to each edition of a book. Each number identifies a specific edition: its format (paperback, hardcover, or digital), publisher, and title. The purpose is to allow bookstores, libraries, and distributors to identify books without ambiguity.

ISBN provides no information about the quality or copyright of the edition. It is a numbering system only; it is used for data storage, commercial ordering, and library catalogue searching.

Brief history

The system originated in the 1960s in the United Kingdom, where a nine-digit numbering system called the Standard Book Number (SBN) was created. It was later adopted internationally and expanded to ten digits. In 2007, a thirteen-digit format was introduced to align with the barcode system used for goods in international commerce.

Structure of the number

The thirteen-digit format has five components: a prefix (usually 978 or 979), a group or language code, a publisher code, a title code, and one check digit—a mathematical digit used to verify that the number was written correctly. The length of the middle sections varies: publishers with high output are assigned shorter codes so they can have longer title codes.

Administration and allocation

The system is overseen by an international body called the International ISBN Agency, which distributes group codes to national or regional agencies. These agencies then distribute publisher codes to publishers in their countries. Fees and application procedures vary from country to country; some are free, while others are paid.

Use and limitations

Each edition of a book requires its own ISBN; for example, a paperback and an e-book do not share the same number. Publications such as newspapers and periodicals use a different system called the ISSN. Many self-published books, particularly digital ones sold through networks, do not have an ISBN.