The best way to get your books included is to speak with your publisher and encourage him/her to join the Google Books Partner Programme. You can direct him/her to the Partner Programme homepage to learn more about how this programme can help increase your books' sales.
If you are self-published, or if the rights to your book have reverted back to you, you can join the programme yourself by sending us your books or uploading them in PDF format. Check out our Author Resources page to learn more.
Note that your books must have ISBNs in order to be included. (An ISBN, or International Standard Book Number, is a number that uniquely identifies published books worldwide. Valid ISBNs consist of 10 to 13 digits preceded by the letters 'ISBN'. For more information on how to obtain one for your book, please visit www.isbn.org.)