That's pretty old. I'd say more than 7 months or so.
Why can't I read the entire book?We respect copyright law and the tremendous creative effort authors put into their work. So, unless any given book's publisher has given us permission to show sample pages, you'll only be able to see the Snippet View which, like a card catalog, shows information about the book plus a few snippets – a few sentences of your search term in context. If the book isn't under copyright at all, you can browse the entire book in the Full Book View, but the aim of Google Book Search is to help you discover books and learn where to buy or borrow them, not read them from start to finish. It's like going to a bookstore and browsing – with a Google twist.