ISBNnúmer

ISBNnúmer is the Norwegian term for International Standard Book Number. It is a unique numerical commercial book identifier intended to be a unique identifier for books. Originally conceived as a 10-digit number, it was expanded to 13 digits in 2007. The ISBN system is managed internationally by the International ISBN Agency and nationally by designated ISBN agencies in each country. An ISBN uniquely identifies a specific edition of a book. For instance, a hardcover edition of a book will have a different ISBN than its paperback edition, or a translated version. The ISBN is typically found on the copyright page of a book and also on the back cover. It is composed of five parts, separated by hyphens, which indicate the group or country, the publisher, the title, and a check digit. The check digit is a single digit calculated using a specific algorithm, which helps to detect errors in ISBNs. ISBNs are used by booksellers, publishers, libraries, and other members of the book industry for ordering, inventory control, sales tracking, and data management. It is a crucial tool for the efficient global trade of books.