Why is the Download button only available on some books?
In Google Books, only books in the public domain — books whose copyrights have expired — have the download feature available. For users in the United States, this typically means books published before 1923. For users outside the U.S., we make determinations based on appropriate local laws. As with all of our decisions related to Google Books content, we're conservative in our reading of both copyright law and the known facts surrounding a particular book.
Please note than many classic novels whose original editions are in the public domain have been republished, often with additional content, and we treat these newer editions as copyrighted works. Google respects and protects the copyrights of all publishers, and in-copyright editions of these works are not available for download unless they're available through Google eBooks, in which case digital editions can be purchased.
Please note that certain public domain works may not yet have Download buttons. We are working to include this button on all public domain works as quickly as possible. We appreciate your patience.