The number of print books and eBooks published every year is going up, and tracking all of those books and files is not easy to do. To facilitate the tracking of books through retailers and other places, publishers and authors use International Standard Book Numbers (ISBNs). The application of ISBNs in the eBook world is commonly misunderstood, so let’s try to clear up the confusion.
According to the International ISBN Agency, every format of a book that you sell must have its own ISBN assigned to it. That means if you print a book in paperback and also in hardback, each one of those formats will require its own ISBN. Because most eBooks require at least two formats (Kindle and ePub), you should also have two separate ISBNs to assign to each of those. In addition, if you decide to create a unique eBook file specifically for one retailer (for example, an enhanced ePub file to sell in Apple’s iBookstore), then that file would also require its own ISBN.
There is no such thing as an “eISBN”. All ISBNs can either be assigned to an eBook or a print book, and there is no difference in the number or the type. Also note that while both Amazon and Barnes & Noble do not require that the files you give them have ISBNs, it is still the best practice to do so.
Purchasing ISBNs in the U.S. is not difficult to do. All ISBNs in the U.S. are registered through Bowker. Go to their MyIdentifiers.com website and follow the instructions to purchase the ISBNs you need. We usually recommend that you purchase at least a block of 10, since that is the same cost as two. You can hold onto the extras until they are needed for future publishing projects.
Other countries have different agencies that manage the registration of ISBNs, sometimes free and sometimes for a charge. You can find a list at the International ISBN Agency’s website.