Google has added a new feature to the books knowledge card, the option to preview the book in Google Books. Now, this may come up when you search for a book title in the Google web search box, it also may not depending on the licensing rights.
For example, a search on [milk and honey book] brings up the book knowledge card on the right side of the search results and has a new link to "preview book" on Google Books.
Here is a screen shot:
Stephen Settanni shared this with me on Twitter.
Forum discussion at Twitter.