When the child becomes old enough to read on their own, have a set 'bedtime' where the child must be in bed. But allow them to keep the light on, and stay awake as long as they are reading. No reading means no light. My parents did that with me. As a child I would get upset that I had to go to bed so I would get revenge by staying up late reading. I always wound up falling asleep, at a reasonable time, while reading. It eventually became such a habit that I could not sleep without a book. I was reading adult level novels by the time I was in regular school. Not because of genius, but because of my parents manipulation.
I've seen this trick work on other children as well, and never fail.
If you use a lamp for the light, just careful. They might start trying to burn thing using the bulb and you will have to remove the lamp. God... damnit....