The ISBN (International Standard Book Number) is an international identification number for books. It marks any book unmistakably, but it does not provide any legal protection.
The ISBN is a ten-digit number divided into four parts:
The ISBN must be printed in the book, preferably on the verso of the title page (copyright page) or on the lower section of the outside back cover. The parts must be separated clearly by hyphens or spaces, e.g.: ISBN 963-7239-13-8 or ISBN 963 7239 13 8.
The ISBN can be converted into a bar code, but the office does not handle it and can not give advice on it.
Printing of the ISBN is mandatory even if a bar code has been created.