ISBNs

An ISBN, or International Standard Book Number, is a code which aids readers, bookstores (both brick and mortar and online), other merchants, libraries, etc., in finding your book and in finding basic, crucial information about your book. 

In some countries (Canada, for example), ISBNs are free: you just need to get one! If you're in Canada, check out ISBN Canada (click link). 

In other countries (like the U.S.), you have to pay a fee to obtain an ISBN. 

If you will be traditionally published (by "traditionally," I mean a publishing house is paying for the expenses of the production of your book), the publisher will provide an ISBN, and they will own the rights to that published form (though the copyright of the book is still yours). 

If you are hiring/paying a publishing house to produce your book, that publisher may provide you with an ISBN. Technically, then, they own the rights to your book (in your package deal with them, you pay for the ISBN they provide; you do still have copyright). 

If you are self-publishing, you need to decide whether or not to purchase your own ISBN. You do not HAVE to have an ISBN to publish, but most authors I work with choose to use one. 

I advise against buying a 3rd-party ISBN to save money as a self-publisher. While you can find discounted ISBNs from companies online, the ISBN remains theirs, not yours. Their "ownership" will show when your ISBN is registered.

Buy from the source! In the U.S., the source is Bowker. Now, single ISBNs aren't cheap here. But they provide peace of mind and the advantage of helping others find your book. I think of an ISBN as an extra layer of protection above your innate and even registered copyright. 

You need an ISBN for EACH format of a single book:

—Softcover

—Hardcover

—A newly updated edition (with any interior updates beyond basic proofreading changes; if you change just the cover, no new ISBN is needed) 

—eBook (not required; but they are commonly assigned for the advantages above)

If you're in the US buying from Bowker, a single ISBN is $125.00. (Wow, I know...) If you are publishing in multiple formats, or have plans to publish more books in the future, you can buy ISBNs in bulk (starting with a package of 10) and save a considerable amount on each. 

ISBN US: click on Get Started: Order ISBN in the upper right hand corner of the page.*