Your book’s ISBN (International Standard Book Number) is the 10 or 13 digit number assigned to every published book, and identifies things like edition, publisher and physical properties. Each particular edition of any published book has to have its own unique number, so you can’t use the same number if you choose to republish an already published book. The new book must have its own new number. I have seen writers on various forums claim that they’ve used the same ISBN number for both their paperback and their eBook versions, but if they did indeed get away with that they shouldn’t have. A quick squiz at Bowker’s rules (internationally applicable) will show quite clearly that a separate ISBN number is required for each format as well. eBook, audiobook, paperback and hardback. Getting even more picky, you could have MOBI and ePub versions published on different platforms. You could end up needing a whole pile of ISBN numbers for the same book. They aren’t cheap unless bought in bulk though, and many self-published authors would rather spend that money on other aspects of publishing and marketing. So how important is purchasing ISBN numbers for the Indie writer?
CreateSpace will supply a free ISBN number to each edition of any paper book that you publish with them. The only “drawback” to this is that they are listed as the book’s publisher on its landing page. CreateSpace isn’t named as publisher in the actual paperback – all you’ll see there is Made in the USA, Charleston, SC, and the date of publication. Very few purchasers will take note of this, or have any sort of clue what it signifies. You are not allowed to list any publishing imprint if you use a free ISBN from CreateSpace. You can if you buy one through them for $99, or you can purchase and supply your own. You can purchase ISBNs from Bowker in the USA or Nielsen in the UK.
Amazon doesn’t care at all whether or not you buy and supply your own ISBN number. They use the ASIN numbers that they assign anyway. The good thing about that is that you can assign your own publisher name both in your eBook and also on its landing page while still using only an Amazon ASIN number.
It is much nicer to have your own ISBN numbers, and to be able to list your publishing imprint on CreateSpace books, but absolutely not necessary if you can’t afford it, or are just starting out in the industry. At a later date you can publish a new edition with your own number if you choose to. CreateSpace and Amazon being listed as the publishers of the book has absolutely no effect on your copyright. Copyright only has to be legally registered in too few countries around the world to mention. The Berne Convention for the Protection of Literary and Artistic Works has us covered anyway. Unless you intentionally sign a contract handing over your copyright it is owned by you.
If you want to try and sell your books in bookstores and go for a printer like Lightning Source then you must have your own ISBN, but be aware also that books sold this way must be heavily discounted and you must make provision for returned books too, so unless you’re pretty sure of knockout sales this way, think twice.
So, the final breakdown as far as I can see is that if you can comfortably afford to buy your own ISBNs then do, but if you can’t then don’t worry about it at all. CreateSpace free issues and Amazon’s ASINs are perfectly respectable and the sort of thing that most readers won’t notice.