Use an e-reader. They are great. Incredibly cheap and sturdy. The screen light on e-readers do not interfere with sleep and hormones, as they're shone on the page instead of blasted into your eyes. After some time with an e-reader you will consider it one of the best purchases you've ever done.

Reading boring/difficult but important books is the best solution when you can't sleep. Either they're the best sleeping pill, or you're learning something important.