Many e-readers can read PDF's, but they may have limits as to what they can do with them. Mine (pocketbook 360) for example can reflow the text of a pdf so that it can fit on the screen easily, but some cannot. It means that sometimes you have to page down and page down or zoom in and out to read everything, which can be rather annoying, compared to a proper ebook which nicely fills up the screen - no more, no less.