Many of the books in Google Books come from authors and publishers who participate in our Partner Program. For these books, our partners decide how much of the book is browsable — anywhere from a few sample pages to the whole book. Some partners offer the entire book in a digital edition through Google eBooks, in which case you can purchase the book.
For books that enter Google Books through the Library Project, what you see depends on the book's copyright status. We respect copyright law and the tremendous creative effort authors put into their work. If the book is in the public domain and therefore out of copyright, you can page through the entire book and even download it and read it offline. But if the book is under copyright, and the publisher or author is not part of the Partner Program, we only show basic information about the book, similar to a card catalog, and, in some cases, a few snippets — sentences of your search terms in context. The aim of Google Books is to help you discover books and assist you with buying them or finding a copy at a local library. It's like going to a bookstore and browsing — with a Google twist.