Buka

Buka is a free, open-source book management system in its relatively early stages of development. It features a simplified interface with controls that become visible only on hover and are easy to navigate. Buka allows you to create searchable book lists, as well as display them by author. Books open in an interface reminiscent of Okular, the common KDE document viewer (dark theme is available). A particularly interesting feature is the built-in translator, which works offline. Buka currently only supports PDF books.