Calibre is an e-book manager. It can view, convert, edit and catalog e-books in all of the major e-book formats. It can also talk to e-book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e-books for convenient reading. It is cross platform, running on Linux, Windows and macOS.
This is the unofficial AppImage built from the official Beta portable package.
Screenshots

Install
If this does not work, see FAQ#1
If this button doesn't work, see FAQ #1
How to install?
Screenshots
Sites
Sources
Exact match
Name match
Description match
No applications found
No applications found matching "{0}"
Try selecting "All architectures" or broadening your search keywords.
Check for typos or try searching with different keywords.
Clear search
{0} results
Failed to load apps.