International Standard Book Number (Isbn)

Unique 10-character number assigned to every non-serial publication sold in trade, and which also serves as its Universal Product Code (UPC). ISBN specifications are governed by the ISO standard 2108 which covers “printed books and pamphlets (in various bindings), mixed media publications, other similar media including educational films/videos and transparencies, books on cassettes, microcomputer software, electronic publications, braille publications and maps” but excludes serial publications and musical recordings as they are covered under separate schemes. The code is divided into four parts usually separated by a hyphen: three fields (all digits) and a checksum character (which may be a digit or the letter ‘X’).