If you're looking to build something useful, consider:
No text is viewable. Only bibliographic data (ISBN, author, publisher) is available. google books downloader github
Highly customizable and run on any operating system. If you're looking to build something useful, consider:
: Press F12 or Ctrl+Shift+I and select the Console tab. google books downloader github
Most of these tools are not "hacking" tools in the traditional sense. They operate by automating what a human user can already do in a browser.