What the heck is an ISBN? Why do we need one? Do we only need one? Where do we get them? ISBN numbers raise many questions and the answers can sometimes be surprisingly difficult to track down.
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Let's dig into the who, what, where and how of ISBNs.
### What is an ISBN?
The ISBN is a numeric identifier that is used around the globe by book stores, publishers, and just about everyone in the publishing industry. ISBNs have either 10 or 13 digits (all ISBNs assigned after January 1, 2007 have 13 digits). AN ISBN is unique to each book. No matter where your book is sold in the world, the ISBN identifies it as YOUR book.
### How many ISBNs do I need?
This gets a little tricky. A separate ISBN is required in each of these situations - *sometimes*.
1. A hard cover edition
1. A soft cover edition
1. An electronic edition (EACH FORMAT) such as ePub and KF8
1. Each **substantial** revision of the book
**Substantial** means changing blocks of content. Redoing your cover does not require a new ISBN. Adding a chapter does require a new ISBN.
But there are exceptions. For example - Amazon assigns an ASIN number to your book which is what they use to list it. Thus, you don't need to use an ISBN either for a Kindle version or a book that will ONLY be sold in the Amazon marketplace without Expanded Distribution.
Likewise, the iTunes store, the Google Play store, and the iBooks store don't require an ISBN for the electronic versions of your book that is placed in their storefront. They also use an internally generated number to identify your book.
But it should be noted, not using an ISBN will mean that you can not sell copies of your book outside of these marketplaces. Their internal identifying numbers are for their store only.
### Where can I buy an ISBN?
There are over 160 ISBN Agencies worldwide, and each ISBN Agency is appointed as the exclusive agent responsible for assigning ISBNs to publishers residing in their country or geographic territory.
In the U.S., the only authorized source that handles ISBN sales is Bowker. [You can purchase from them directly from Bowker here](https://www.myidentifiers.com/ )
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Your own ISBN will carry your name or company name as the publisher as well as the author. However, if you don't care who the publisher is, some publishing sites such as CreateSpace will assign a free ISBN to your work, but they will be listed as publisher. Some retail outlets won't buy titles that use CreateSpace as the publisher, but the number of bookstores that refuse to buy CS published titles has dropped over time and in most cases is not a factor in the CS Expanded Distribution.
If you publish through [Ingram](https://www.ingramcontent.com/), or [Book Baby](https://www.bookbaby.com/) or someone similar, they also offer ISBNs which they have purchased through Bowker in large blocks for resale. Sometimes they offer plans that will allow you to be listed as publisher. The cheapest plan will have them listed as publisher.
#### If you use your own ISBN - you must go back to Bowker and register that ISBN once you have assigned it to a book title.
### How much does an ISBN cost?
Some countries and territories provide ISBNs at no cost. The U.S. can become quite expensive, with one ISBN going for $125. But watch for sales and coupons which occur several times throughout the year and consider buying in blocks. A block of 10 is $295, a block of 100 is $575 - a substantial saving!
### Does an ISBN automatically get my book into the Library of Congress?
NO - but you must have an ISBN before you apply for that LCCN (Library of Congress Catalog Control Number) Here is a [good article on the fairly painless process of obtaining an LCCN](https://authoru.org/authors-how-to-get-your-lccn-library-of-congress-number.html)
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### Does an ISBN give me copyright protection?
Nope. Your work is protected under copyright the second you release it to the public - no matter what form that release may take. You can issue take down notices to the server host or social site that is illegally allowing your work to be downloaded or stolen. BUT if you want to win in court, that copyright must be registered with the [US Copyright office](https://www.copyright.gov/registration/)
It is unlikely you will even find an attorney to handle a copyright case without having that copyright registered.
I hope this clears up at least some of your ISBN questions. They are an important detail for every published book. Without them your book can not be sold to brick and mortar outlets, get into the Library of Congress, or even end up on lending library shelves. But if you're only doing an eBook on Kindle or publishing on Amazon using CreateSpace, you can save yourself the cost of an ISBN and go with the ASIN Amazon assigns and the ISBN CreateSpace will assign.
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