The International Standard Book Number: a four-part, ten-character identifying code given a book (a non-serial literary publication) before publication. The four parts are: group identifier (e.g., national, geographic, language); publisher identifier; title identifier; title identifier; and check digit. Started by British publishers in 1967, the standard book number has been an international standard since 1969. The numbering system is administered among cooperating publishers in participating countries by a standard book numbering agency. Most IEEE Xplore® conference publications have a unique ISBN.