Tuesday, December 20, 2011
A new recommendation for assigning ISBNs to ebooks has been out a couple of weeks. I remarked earlier on why this didn't make sense to assign two different numbers to the EPUB ebook and MOBI ebook of the "same" ebook when the only operation was to take the EPUB one and use an automatic software converter (e.g. Calibre) to convert the EPUB ebook into the MOBI ebook. This is mainly done now simply because Amazon does not "read" EPUB, and the publisher has to produce a MOBI version for its Kindle customers. (In a way, this would be like asking a publisher to assign different ISBNs to a hardcover book depending on which bookseller chain store they sell that book in.) The EPUB ebook on the NOOK and the corresponding MOBI ebook on the Kindle "look" the same and have exactly the same HTML/CSS content. It doesn't make sense that they would have a different ISBN simply because one is reading that ebook on a Kindle vs. a NOOK.
The point is: If it's a basically automatic conversion that takes your EPUB ebook and produces that ebook in a different e-format, the ISBN stays the same. However, if one uses features of a particular format to really distinguish the ebook in that format (i.e., there is no simple, automatic way to convert it to another format), a different ISBN should be assigned.
(PDF is a curious exception. It is a fixed, not a reflow, format and is used for printing. There are converters of course that take an EPUB ebook and automatically creates a PDF file. Perhaps they would be useful to send one's EPUB ebook to a POD machine.)
Now there is a new format on the block: KF8 from Amazon. If one publishes an ebook that uses KF8-specific features that truly distinguishes it from the EPUB version, then it's a different ISBN. That makes sense.
CDF (Computable Document Format) may be an upcoming one for math ebooks.
Now some ebooks are being published as apps: iOS vs. Android. Here, the recommendation should be the same: If one starts with the same base version of the ebook (e.g. HTML5) and uses a tool that automatically produces the two different apps (iOS, Android) with the same ebook (HTML5) base, the ISBN would be the same. However, if the publisher uses iOS and/or Android dependent features to distinguish the two version, then it's two ISBNs.