What are PDF downloads?
Google Books has always helped users discover and read out-of-copyright books online. With the addition of PDF downloads, Google now allows Internet users all over the world to download (and therefore print and read offline) these same out-of-copyright books. To find books you can download for free, select Full view books when entering your search terms. Clicking on the Download button shown on public domain books will allow you to download a PDF of the book to your computer.
Some Google eBooks are also available as PDF downloads once they've been purchased. These downloads may be secured with DRM (Digital Rights Management), which may restrict the ability to print them.