Is it possible for 3rd party ebook readers to display books bought through the iBook store? If the answer is "no" then this seems like a great way to ensure bad

Is it possible for 3rd party ebook readers to display books bought through the iBook store? If the answer is "no" then this seems like a great way to ensure bad ebook software on your platform. Case in point: no one seems to really like the iBook app very much.