Google Books is useful for finding a variety of content typically provided in book format. It's important to remember that not ALL books are available directly in Google Books.
Typically, you can locate the following in Google Books:
You'll have the most success locating full-text versions of books if it is out of copyright. In the United States, books are copyrighted for 70 years, plus the life of the author. So, think of books from the early to mid-twentieth century or earlier. Think of classic titles and authors when searching for full-text, free online copies.
Recommended Search Strategies:
1. Look for the "Free Google eBook" link.
2. Input your search term. Select "Google eBooks" + "Free Google eBooks."