The International Standard Book Number (ISBN) is a unique numeric commercial book identifier based upon the 9-digitStandard Book Numbering (SBN) code created by Gordon Foster, Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers WHSmith and others in 1965.
The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108. However, the 9-digit SBN code was used in the United Kingdom until 1974. An SBN may be converted to an ISBN by prefixing the digit “0”. ISO has appointed the International ISBN Agency as the registration authority for ISBN worldwide and the ISBN Standard is developed under the control of ISO Technical Committee 46/Subcommittee 9 TC 46/SC 9. TheISO on-line facility only refers back to 1978.
Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure; however, this can be rectified later.