I recently reviewed the Gwibber Lens for the Ubuntu Unity Launcher. Google Books Lens is another Unity Launcher Lens for Google Books users, which allows easily searching for books, authors and topics via Google Books.
Post Update: This lens has not been very functional and it is advised that users should avoid using it, since it is unlikely to work for most users.
To install Google Books Lens, enter the following commands in the Terminal:
sudo add-apt-repository ppa:davidc3/books-lens sudo apt-get update sudo apt-get install unity-books-lens
After installing the Google Books Lens, log out and login again for the changes to take effect. Or hit ALT+F2, enter Unity –Replace and click on it. The lens is displayed in two portions, the first part shows books from Google Books in accordance to your typed key word, whereas, the half displays relevant information from Wikipedia. You can launch the lens anytime from the launcher or by hitting the Windows (Super Key)+B.
To see a demo of Google Books Lens, check out the below video:
In case you would like to know the procedure to remove any installed lens, see my post: How To Remove A Unity Lens In Ubuntu Linux. You can also download the Deb package from the Launchpad link given below: