I never quite feel as if my story is ready and available for sale to readers until it gets stamped with its ISBN. It’s like a ticket that gets me into the ballpark. There’s something both official and exciting about it. Ah, at last I’m published. 
The Literary Social Security Number
ISBNs (International Standard Book Number) are numerical codes assigned by both traditional and indie publishers that are the unique identifier for your book. ISBNs are only for physical copies in hardback and paperback. An ASIN (Amazon Standard Identification Number) is assigned only by Amazon to the Kindle edition, and is used exactly like the ISBN. The ASIN is a mix of letters and numbers.
ISBNs and ASINs are like your book’s Social Security number. No other book has that exact ISBN and won’t as long as it’s in print. Further, each edition of your work will get its own unique number. If you went with a traditional publisher, your book would get one ISBN for the hardback, a second for the paperback, and a third for the Kindle version. I self-publish, so I get an ASIN for my Kindle version, an ISBN for my Smashwords version, and a second ISBN for the CreateSpace paperback version.
How do I Get One?
When you publish traditionally with a large or small house, they will assign ISBNs to the hardback and paperback versions.
My self-published books automatically receive their ISBNs and ASINs during the book-creation process. When I put together the Kindle version, Amazon.com automatically gives me the ASIN. My Smashwords and CreateSpace versions each get an ISBN.
So, don’t worry about purchasing ISBNs or whether you’ll have to pay for them when digitally publishing your stuff. They’re free and they’re automatically assigned. Whoever decided that should get a free pint at the pub from every writer!
What are They For?
ISBNs/ASINs are used for legal, copyright, story right, intellectual property, tracking, and inventory purposes. When you sell your story rights, the buyer will need the ISBN/ASIN. Amazon.com and Barnes and Noble, in addition to every other brick-and-mortar bookstore, track inventory and sales using these numbers.
I have a list of all of my stories and their ISBNs/ASINs, since it’s easiest to keep them all in one location. They’re similar to a car insurance card – you can forget about it for 90% of your life, but when you need it, you NEED it.
Read more about ISBNs on Wikipedia.
Like copyright, ISBNs and ASINs are a necessary and legal part of being a writer. Luckily, the self-publishing industry is set up so that obtaining them is pretty painless. Once your story is all safe and sound with its literary Social Security number, you can start earning royalties and get paid!
And that’s what we’re all here for, right?
