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What is an ISBN and Why Does My eBook Need One?

13 very important numbers for every eBook

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.

R.R. Bowker is the official agency in charge of assigning and maintaining these numbers in the US. For other countries you can find your local agency here:

Publishers and authors can buy blocks of their own numbers.

A self-published author can buy just one ISBN for $125. 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.

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4 Responses to “What is an ISBN and Why Does My eBook Need One?”

  1. Klausss May 12, 2015 at 12:55 pm #

    Hey there bookbaby,
    a ISBN number for eBooks is not necessary for eBooks if I only want to publish on e.g. Amazon KDP, right?!

    • Niky May 17, 2015 at 7:40 pm #

      hy,I have the same problem.I want also to publish a kindle book.what is the difference anyway between kindle and e-book?1if i want to publish on both forms?
      by the way…what is about the publishing rights for a kindle book?


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