An ISBN (International Standard Book Number) is a specific 13-digit number that identifies your book and book-like products, such as audio books and ebooks, and has been the standard of book identification since 1970. The purpose of an ISBN is to establish and identify one title or edition of a title from one specific publisher.
Each format (hardback, paperback, audio book etc) of a book requires it own ISBN number.
ISBNs never expire and there are no renewal fees.
The online web address for ISBN acquisition is