I needed to have a book on hand at all times. Since all the other solutions here are in python, I had to write a script in BASH.
To install files:
git clone https://github.com/SysAdmln/calameo-download-pdf
MacOS
brew install imagemagick
Debian
apt install imagemagick
Usage
cd calameo-download-pdf
chmod +x ./calameo.sh
./calameo.sh url