Calibre is a free e-book library manager, not that I've done much with that feature yet. There are many elements, including a news feed handler, that I think I might like if I'd take the time to investigage them, but right now I'm very happy just using the feature for which I installed it: Calibre converts all sorts of other e-book formats into something my Kindle Paperwhite can read. Suddenly I'm drooling over Project Gutenberg and the Christian Classics Ethereal Library. What's more, my Kindle was supposed to be able to handle pdf files, but was not doing at all well with them; Calibre quickly and easily solved that problem.
There's one thing Calibre won't do. I purchased a book in ePub format, even though my Kindle Paperwhite can't read it, because I knew that Calibre could easily convert it for me. However, it turns out the book has some sort of Digital Rights Management lock, so Calibre won't touch it. I can't even read it, except on my computer. This is my first encounter with DRM and I am not happy. There must be a better way for authors to get duly paid, without keeping me from reading a book I paid for -- particularly since the book said it was good for "up to six devices." I feel as I did when I bought a DVD in Japan and it wouldn't work in my American DVD player. :(
So be forewarned.