ISBN

International Standard Book Numbers (ISBN's) are a 10-digit identifier assigned to books and book-like products (including audiobooks, movies, etc.) by the ISBN Agency of the nation in which the edition was published. The ISBN is a unique identifier for each edition of a book. For example, hardcover and paperback editions of a book would have different ISBN's. The ISBN of a book can typically be found on its title page, copyright page and/or back cover.

ISBN's use a base-eleven numeric system in which the letter 'X' is used for '10'. Publishers frequently punctuate them with hyphens to separate imbedded identifiers (country code, publisher code, title code, and check digit). However, only the numeric data is relevant to computer searches and most online sources will omit ISBN punctuation.

ISBN's are particularly useful for an online purchase or requesting an interlibrary loan, since they can identify not only the title but the edition of a book without recourse to additional information. A book can be successfully ordered using only its ISBN, without even prior knowledge of its title.

• See Also:ISSN,Online Textbooks