There’s a lot of mixed messages on the net about ISBNs. I’ve read a lot of different articles and sources about them, some of which contradict the other, so there seems to be a lot of misinformation and confusion about how to apply the ISBN to digital books. I went straight to the source (Thorpe Bowker in Australia, but you can find your ISBN provider in your country using the International ISBN Agency website).
ISBN stands for International Standard Book Number. If your book is a family genealogy and you’re only handing it out to family members, then you don’t need to fork out the money for an ISBN. If you’re planning on selling it (even if the list price is a $0 value, i.e., free), then you need an ISBN, as it is a unique code specially assigned to your book. Book retailers and libraries catalogue their books using it and it gives them lots of information. If you release your work digitally, then you’re probably going to need more than one ISBN.
You’ll need separate ISBNs for each file type that you create. Want to sell to Kindle owners? You’ll need a .mobi file. Want Tablets and other eReaders to read your books? You’ll need an .epub file. What about a PDF for download and reading directly on the screen, which can be seen on different ereaders and Tablets as well? Yep, you’ll need one for that too, as well as any other file format you release.
But why? Isn’t one version of a digital book exactly the same as another? It’s the question I asked myself.
Imagine a hardback and paperback of the same book. They have different ISBNs because they’re different products. (This all cycles back to books being products which authors sell, rather than solely a piece of art). They have the same story in its pages, the title and author is the same, they might even have the same cover. Imagine if you spent the money and got yourself a special limited edition of your favourite book in hardback, to display prominently in the hall, greeting guests as they walk through your expansive, marbled foyer. (If you’re going to imagine, do it with gusto). What you end up getting in the post is a miniature mass-produced paperback of the same book, possibly with a different cover. What, now? The author must have used the same ISBNs on both books! Fireballs will zoom out of the sky and zombies will crawl up from the earth, signalling the apocalyptic days ahead.
A little over-dramatic, but this is why separate ISBNs are used. A hard copy in your hands can be different, and so can the digital copy that you download. Your readers would be terribly frustrated if they pay for a file their ereader can’t open because the cataloguing software incorrectly sent them the incorrect version.
So that’s the hard and fast rule to ISBN assignment. Assign one to every different file format and choose wisely what formats you want to release your work in (and absolutely do NOT mix them up!). I’m using at least two (epub and mobi), and if I end up with a print-on-demand version (through CreateSpace), I’ll use they one they offer to assign for free. I have to look at who would use a PDF version before I decide whether to release the book in that format as well.