It seems like Google don’t find it enough to just search information on websites, they want to go further and extend into the offline world, and start searching information that’s in books too.
According to their Google Print FAQ page, they say:
Google’s mission is to provide access to all the world’s information and make it universally useful and accessible. It turns out that not all the world’s information is already on the Internet, so Google has been experimenting with a number of publishers to test their content online. During this trial, publishers’ content is hosted by Google and is ranked in our search results according to the same technology we use to evaluate websites.
Now this could be bad news for Amazon, which is working on a similar full-text book search effort.