You register the book which also gives you a copyright. I believe it is at the library of Congress or something. There are places that will handle it. You then get an ISBN number which makes your book go into the main database used by most of the world. Then if someone searches for a book on autobody work, your book will show up. They can then order it through places like Amazon.com or even have any bookstore order it.
Here are some references.
ISBN reference 1 reference 2 There was a lot more with a google search on ISBN numbers. Also, look at the back of any book you have, there is a barcode and ISBN number.
