ISBNjärjestelmä

ISBNjärjestelmä, or the International Standard Book Number system, is a unique commercial book identifier code. It is a numerical commercial book identifier for monographs published commercially. The ISBN was originally devised in the United Kingdom by David Whitaker in 1965 and established as an international standard in 1970 by the International Organization for Standardization (ISO). The current standard is ISO 2108.

An ISBN consists of ten digits when it was originally established, and thirteen digits since 2007. A 13-digit ISBN is prefixed by ISBN, followed by the 13 digits. The first 13-digit group of numbers is 978, and the 10-digit ISBNs are converted to 13-digit ISBNs by prepending 978 and recalculating the last digit. This change was made to allow for more numbers to be assigned.

The ISBN is assigned to each edition and variation (except reprinting) of a book published. For example, a hardcover edition, a paperback edition, and a e-book version of the same book would all have different ISBNs. This allows for precise identification and tracking of specific book products within the publishing industry, including sales, inventory, and ordering.

The ISBN is not an indexing system, but rather a unique identifier. It does not provide information about the title, author, or subject of a book. It is a way to distinguish one book from another. The system is managed internationally by the International ISBN Agency and nationally by ISBN agencies in each country.