What most naturally follows?

How to add books to google books
Join the google books partner program at the website listed in the sources section of this article.
Verify that you hold the copyright to the books you want to submit. If you are not the copyright holder--the author or publisher--do not attempt to submit books.
You can list books with google books if you're self-published or the rights to your book have reverted back to you. Fill out the forms on the google books website and then send physical books or digital pdf files to google books.