1. A print book ISBN cannot be reused for the eBook.
2. One unique ISBN per format of book. A format is Kindle or ePub (Nook, Apple, etc.), audio book, hardcover, softcover, etc.
3. Change the book beyond typos and you need a new ISBN.
4. There is no such thing as an e-ISBN.
5. You do not need an ISBN to publish using Amazon Kindle Direct Publishing (KDP) or Barnes & Noble Pubit (Nook). [Update: it is also not needed for Apple, Kobo or Google.]
What is an ISBN?
This stands for International Standard Book Number. You will see references to “ISBN-10″ and “ISBN-13.” The 13 version is the same number but with a prefix to identify it as being for book publishing. You can show both numbers in the eBook or print book although only the ISBN-13 is necessary.
How much is it?
$125 for one, $295 for 10, $575 for 100 and $1000 for 1,000 numbers.
R.R. Bowker is the exclusive sales agent in the United States. They have a separate website devoted to this topic: www.myidentifiers.com.
Can you get a free ISBN?
Yes. Some publishing services firms will make it available for free (like Smashwords) while others may charge a nominal amount ($10 to $25 each).
What’s the catch with a free ISBN?
Your name won’t be listed as the publisher. ISBN’s are registered to a “publisher” when sold so if you get one “free” or as part of a publishing package you buy from someone, the master record will show that company as the “publisher”.
If you want to be listed as the publisher you should buy your own ISBN.
When is it required?
It is up to the store selling your book or eBook whether or not you need an ISBN.
What if you have published a book or eBook and you are changing it. Do you need a new one or can you use the old one?
Unless you are making minor changes like fixing typos, you need to assign a new ISBN. Adding more information or changing information requires a new ISBN.
Can you use the same ISBN for both Kindle and ePub?
Yes, if the content is the same in each eBook. Bowker used to recommend separate ISBN for each type of format. Keep in mind that audio books and different types of print books are separate formats and each requires its own ISBN.
Do you put it in the eBook?
Yes, add the number to the copyright page of your eBook.
You can put all the numbers together on the copyright page or add the appropriate ISBN to the file type you are publishing. For example:
ISBN 13: 978-0-9999999-9-9 (Paperback edition)
ISBN 13: 978-0-9999999-9-9 (eBook edition)
If you buy…
Don’t forget to return to your Bowker MyIdentifiers account and complete the information for each ISBN assignment. This is very important! The data is shared with book industry databases such as libraries and other retailers. Without it, they won’t know the book exists should someone ask for it.
ISBN defined (Wikipedia)