One thing I noticed while reading “The Martian” is that getting into something absorbing is great for getting a good night’s sleep. That’s the magic of reading, apart from the fact that I stay up past 1AM because it’s sucked me in!
Maybe once you get to that “got to keep reading point” your brain invests in anticipating and interpreting the story, and keeps on doing so as you turn out the light.
I find it harder to reach this kind of flow state with non-fiction but it does happen. In Chile I remember sitting in my tent reading Nate Silver’s “The Signal and The Noise” by torch-light. It was very effective at relaxing me for sleep. Those were good times.
The next book I plan to read is Adam Tooze’s “The Wages of Destruction” which is about how the Nazis managed to fund the German economy in the run up to the second world war. It’s a difficult book to get hold of: it’s out of print and West Sussex library keeps its copy in the rare books section – that’s the copy I have now. I can only keep it for another five weeks so I figure I’d better get cracking.