One feature that is helpful from
Unity is the Dash. The Dash can help users to find information quickly, either locally (bookmarks, recent files, installed applications, etc) or remotely (Google Docs, Twitter, etc).
This quick search can be presented because the Dash has one or more Lenses. One Lens only gives one category of search result for the Dash. You can search the Lens category from the Dash home screen or through Lens’ page in the Dash. To go to the Lens’ page in Dash, you can click on the icon of the Lens Bar.
Because this post discusses Books Lens, so we'll just add a special Lens for the books category. For other Lens categories, you can find it yourself, see the previous paragraph.
How to Install Book Lens for Unity’s Dash, type the commands bellow in the Terminal: