The International Standard Book Number, or ISBN , is a unique, numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin,for the booksellers and stationers W.H. Smith and others in 1966.
The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO 2108. (However, the 9-digit SBN code was used in the United Kingdom until 1974.) Currently, the ISO’sTC 46/SC 9 is responsible for the ISBN.
An ISBN is assigned to each edition and variation (except reprintings) of a book. The ISBN is 13 digits long if assigned after January 1, 2007, and 10 digits long if assigned before 2007. An International Standard Book Number consists of 4 or 5 parts:
- for a 13 digit ISBN, a GS1 prefix: 978 or 979
- the group identifier, (language-sharing country group)
- the publisher code,
- the item number, and
- a checksum character or check digit.
The group identifier is a 1 to 5 digit number. The single digit group identifiers are: 0 or 1 for English-speaking countries; 2 for French-speaking countries; 3 for German-speaking countries; 4 for Japanese; 5 for Russian, and 7 for Chinese. An example 5 digit group identifier is 99936, for Bhutan. In general, the groups are 0–7, 80–94, 950–993, 9940–9989, and 99900–99999.
The original standard book number (SBN) had no group identifier, but affixing a zero (0) as prefix to a 9-digit SBN creates a valid 10-digit ISBN. Group identifiers form a prefix code; compare with country calling codes.