All About ISBNs

Most likely, if you’re a writer you’re already familiar with what an ISBN actually is. It stands for International Standard Book Number, and is the way books are commercially set apart from each other. The book number is unique for every book, and for every version of a book, like a literary fingerprint. It allows a book to be identified both in catalogs and bookstores, be they physical or digital.

Most people know that a book needs an ISBN, but what they may not understand is that each format of the book needs a separate number. A hardback is different from a paperback, which is different from an epub, which is different from a mobi. An ISBN will reveal exactly what you’re getting, as opposed to other versions available.

If you have a publishing company, they will most likely take care of the process of assigning ISBNs to your work, but a self-published author needs to do that themselves. It’s not a difficult process, but it is an important one.

Getting the numbers.

If you’re in the United States, you attain an ISBN by going to In the United Kingdom you can go to Each country has it’s own dedicated agency to administer the numbers, and it’s not difficult to find on an internet search. They sell the numbers in bulk, in groups of 10, 100, or 1000. Keep in mind that if you’re publishing as both epub and mobi you’ll need two per book. If you make a hard copy version, that’s a third, etc. Each “edition” of a book is also a different ISBN number. You can use them up fast and they’re cheaper in bulk.

The agency will have a form you need to fill out in order to assign a book to a particular number, including information like title, author, publisher, version, etc. It’s important to fill this information out as completely as possible, so have it ready when you’re going to assign the number.

We won’t go into detail about the process, as the agencies have excellent instructions, but there are a few more things worth mentioning.

They say I don’t need one.

Publishing an ebook on the iBookstore or Amazon allows you to enter an ISBN, but may not require one. The production of ebooks on a large scale is relatively new in the timeline of publishing, and not all the rules have been hashed out yet regarding them. It’s very possible that what isn’t required to publish them now, may be required in the future. Keep that in mind if you choose to go without an ISBN in these “optional” circumstances.

No number, no sale.

Some retailers refuse to offer a book if there isn’t an ISBN assigned to it. They use it for their own tracking purposes. By taking the optional non-registered route, you may be limiting yourself in the area of sales and marketing.

How Simply Written does it.

Simply Written provides an area in the book details to enter an ISBN. There is a place for the epub version and for the mobi version, and Simply Written will automatically insert the correct ISBN into the correct file type, leaving the other one out. Make sure to keep track of your ISBN numbers and what they’re assigned to.

For more information on ISBNs, see the website of your national ISBN agency.