Calibre
From Calibre website:
Calibre is a powerful and easy to use e-book manager. Users say it’s outstanding and a must-have. It’ll allow you to do nearly everything and it takes things a step beyond normal e-book software. It’s also completely free and open source and great for both casual users and computer experts.
You can download Calibre here, available on Linux, macOS and Windows.
TODO update ebook TODO series