The ISBN (International Standard Book Number) is a unique 13-digit code assigned to your book to identify it amongst all the others in the digital marketplace.
Retailers use these codes to track and report sales. Every book — physical or eBook — is required to have its own number if it’s made available for sale.In fact: If you’ve already published your book in physical form, you’ll need another ISBN for the electronic version.
Publishers and authors can buy blocks of their own numbers.
A self-published author can buy just one ISBN for $125.
BookBaby.com sells ISBNs for $19 each!
For more information of the basics of eBook publishing, download our free PDF Guide, eBook Publishing: The How-To Guide for Writers.