You will need to install a user script manager extension to install this script.
This is a modified version of GBookDown written by @nikisby (https://greasyfork.org/en/scripts/17113-gbookdown-download-google-books)
It is updated to work with current version of Firefox (65 as of writing) and Tampermonkey and have added a page range.
It is not perfect as two of the included JS scripts are out of date, but it's working for now.
TO use it, just install Tampermonkey on Firefox and add this script. Some VPN / Tor stuff may be required, see instructions from the original script: https://drive.google.com/file/d/0B_x__uIHJMFxdEc0X1piMlpzZUE/view