One of the more disturbing trends in eBook publishing centers around the use—or lack of use—of ISBN numbers to identify editions of eBooks. The fact that many of the larger stores do not require them at all is in itself a challenge. But when publishers and stores use the term “eISBN”, or use the same number for fundamentally different eBooks, it creates confusion. This has the potential of upsetting readers and ultimately creating problems for the industry as a whole.
(Google uses the term eISBN. Kobo does as well but now they acknowledge “You might see this informally called an ‘eISBN'…”)
There is no such thing as an eISBN
Technically you need to assign a unique number for every eBook edition: EPUB, Mobi (Kindle) and PDF are unique digital media formats, with unique capabilities. For example, PDF is great at displaying a replica of a printed page. It can have any type of font or layout. But an EPUB or Mobi file is reflowable text with a limited selection of fonts. Using the same ISBN number communicates they are the same.
NOTE: See our post ISBN Essentials: An FAQ for eBook Publishers for clarification on the need to assign a separate ISBN for each eBook file (i.e. one for Kindle and different one for EPUB).
Different products require unique identification
The PDF vs. EPUB/Mobi example is easy to understand and is less of an issue today because the major stores do not sell PDF eBooks. But with an ever-increasing interest in using multimedia elements—audio, video, animation—to enhance text and image eBooks, using the same number for different products will confuse shoppers. Making matters worse publishers give fundamentally different eBooks the same exact title.
One title I reviewed a few months ago was the Boston Globe's 68 Blocks. The version in the Apple iBooks store is a completely different product than the eBook in the Amazon Kindle store yet their branding is exactly the same . In fact the Apple product was authored with the proprietary iBooks Author authoring tool and differs from the Kindle edition significantly. (Amazon's mobi is also considered proprietary but at least you can use a free conversion tool like Calibre to create an EPUB file from a non-DRM mobi file. You can't do that with the Apple .ibooks format.)
Another example is the popular children's book Chicka Chicka Boom Boom. Purchased from Amazon the eBook's text can be enlarged by double clicking and there is no sound. Purchased from Apple's iBooks store (at four times the price as of this writing) the shopper gets a book enhanced with audio read-along. Both eBooks share the same ISBN number: 978-1-4424-3891-0.
Contrast these examples with the superb Warner Bros series Inside the Script (unfortunately it is no longer published as of 2021). The differences between the Kindle and iBooks editions are recognized by the use of different ISBN numbers.
Best practices for eBook publishers (and other industry stakeholders)
- Use an ISBN.
- Assign a unique ISBN to each format of the book (print, eBook, audiobook).
- Stop using the term eISBN!
What I find interesting is that the publishers and stores are not making a bigger deal out the differences between their eBooks. From what I've read most Apple device owners use or prefer Amazon Kindle eBooks over Apple iBooks. This would be an opportunity to differentiate Apple's superior eBook presentation from Amazon's inferior enhanced eBook presentation.
Have you come across eBooks that share the same name but differ in their content, capabilities or presentation? Let me know in the comments box below.