There’s a lot of misinformation out there about ISBNs, so I’ve compiled this brief guide to answer some of the most common questions we get on this topic. An International Standard Book Number is “assigned to each book by its publisher under a system set up in the late 1960s by the R. R. Bowker Company and the International Organization for Standardization (ISO).” The ISBN is your book’s unique identifier and enables inventory tracking and order fulfillment (CMS 1.32).
A single agency manages and sets the price for ISBNs in each country, and in the United States that agency is Bowker. According to the Bowker website, “[t]he purpose of the ISBN is to establish and identify one title or edition of a title from one specific publisher and is unique to that edition, allowing for more efficient marketing of products.”
ISBNs are not cheap, and depending on your publication and distribution strategy, you may not need to purchase any. For example, if you’re publishing a Kindle version only and you don’t supply your own ISBN, Amazon will assign your book an Amazon Standard Identification Number (ASIN). Even if you want to publish both print and ebook versions, if you plan to publish and distribute exclusively through Amazon and you don’t mind CreateSpace being the publisher of your work, you can do so without purchasing an ISBN.
So why would you want to buy your own ISBNs? Because the entity that purchases the ISBN is permanently identified as the publisher of record, which means that you can’t move your book to a different author-services company later if you don’t own the ISBN. Not only that, but libraries and reviewers often don’t take books with author-services companies as the publisher of record seriously.
In most cases, we recommend that indie publishing authors purchase a package of ISBNs. A single ISBN costs $125, whereas 10 sell for $295 and 100 for $575. If you plan to publish in print and digital formats, the 10-pack is your best bet. According to the Chicago Manual of Style, “[e]ach format or binding must have a separate ISBN (i.e., for hardcover, paperbound, CD-ROM, e-book format, etc.)” (CMS 1.32).
“However, an ebook that you sell via Amazon, Apple, Barnes & Noble, Google Play, and Kobo are considered the same entity and require only one ISBN” (APE 211). In other words, your epub and mobi files use the same ISBN. Bowker will try to tell you different, but their own explanation of the purpose of an ISBN “to ‘allow for more efficient marketing of products'” contradicts that.
From a marketing perspective, an ebook is a single entity. Anyone with a computer can purchase an ebook in any format and have a way to read it. You don’t need an e-reader to read an ebook, so file format (epub, mobi, or pdf) doesn’t really matter when you’re marketing your ebook. Furthermore, you shouldn’t have to pay for a new ISBN every time some tech-head comes out with a new proprietary e-reader with its own special format (like Kindle’s mobi). And there’s nothing saying that you have to.
You do need separate ISBNs for hardcover, paperback, and audiobook versions, or if you write a second edition. Again this goes back to how books are traditionally marketed and how sales statistics are calculated: “Bestseller lists such as the New York Times and the Wall Street Journal may not combine the sales figures of your ebook and printed book. Sales of softcover and hardcover are counted in different lists too” (APE 211).
In any case, while you don’t necessarily need ISBNs, they do add credibility to your book and help you keep your publishing rights. Want more information? Check out our sources:
- Bowker Identifier Services, https://www.myidentifiers.com/product_isbn.
- The Chicago Manual of Style (CMS), 16th ed. (Chicago, IL: University of Chicago Press, 2010).
- Guy Kawasaki and Sean Welch, APE: Author, Publisher, Entrepreneur?How to Publish a Book (Nononina Press, 2013).