Yep! I load mine in from Calibre and they work fine. The only things that haven’t worked for me are comic book files (ie .cbr and .cbz files) and some .pdfs. Not sure why some of them work and some don’t lol. But if you use the stylus to click on a book to open it, you’ll get a pop-up if the stylus won’t work with it.

Yes. I side load all of my books and was writing on them yesterday.