You can read amazon drm encumbered books with amazon cloud reader. You can run adobe digital editions via wine.
You can also read your ebooks on your nook, kindle, or tablet which would probably actually be a better experience.
You can buy dead tree books.
You can buy non drm encumbered books.
You can buy dead tree books and then go and download a digital version of the same work from library genesis knowing that you have supported the author but not drm. Then you can read on whatever device you like.
If you are poor you can skip the first step and just read the books.
Your local library still exists and is positively full of books.
Many libraries provide free access to technology books via Safari Books.
The claim that you can't enjoy books without windows is a curious claim when so many options exist.
Which services don't work on linux other than itunes?