First, number all of your books on the spine, starting with 1. Then create a database keeping track of the specifics on each book (number, title, author, topic, publish date, etc). On your bookshelf, just make sure that all of the numbers are in order. When you want a book, lookup the book number in your database, go to the bookshelf and easily find its number.
Slashdot Mirror
If memory serves me correct, that technology was called SmartSound. And as far as I can remember, Magnavox was sued over it, and lost.
First, number all of your books on the spine, starting with 1. Then create a database keeping track of the specifics on each book (number, title, author, topic, publish date, etc). On your bookshelf, just make sure that all of the numbers are in order. When you want a book, lookup the book number in your database, go to the bookshelf and easily find its number.