calibre

calibre manages a library of e-books. Books are added from disk or from a connected device, metadata is edited in a form or fetched from online sources, and the library is browsed by author, series, tag, rating or any custom column you define. The library itself is a folder of book files plus a database index, so the files stay where you can see them.

Conversion is the other half. calibre reads and writes the common e-book formats — EPUB, MOBI, AZW3, FB2, TXT and others — and takes PDF as an input with the caveat that fixed page layouts convert poorly to reflowable text. Options control the output profile, styling, structure detection and table of contents. A separate editor works on EPUB and AZW3 internals, and the built-in viewer supports annotations.

The content server publishes the library over HTTP for reading in a browser. News recipes turn websites and feeds into periodicals on a schedule, and device drivers copy books to e-readers over USB.