kirjanumero

Kirjanumero, also known as ISBN (International Standard Book Number), is a unique identifier assigned to books for the purpose of international trade and cataloging. It consists of a series of numbers and sometimes letters, which are used to distinguish one book from another. The ISBN system is overseen by the International ISBN Agency, which is part of the International Organization for Standardization (ISO).

The ISBN is typically found on the back cover of a book, near the barcode. It is a 13-digit number, although older books may have a 10-digit ISBN. The first three digits of the 13-digit ISBN represent the country or language area, the next group of digits represent the publisher, and the last digit is a check digit used to verify the accuracy of the number.

Kirjanumero serves several important functions. It helps libraries and bookstores to manage their inventory, facilitates international book trade by providing a standardized identification system, and aids in cataloging and indexing books in databases. Additionally, the ISBN can be used to track the sales and distribution of books, which is valuable for publishers and authors.

The ISBN system has evolved over time to accommodate changes in the publishing industry. For example, the transition from 10-digit to 13-digit ISBNs was necessary to accommodate the growing number of books being published worldwide. Despite these changes, the ISBN remains a crucial tool for the identification and management of books in the global publishing industry.