I just find it the most amazing thing. 8 hours a day, we all do it, and we don't know why. It's akin to having part of the globe unexplored. Anyone got any rec

I just find it the most amazing thing. 8 hours a day, we all do it, and we don't know why. It's akin to having part of the globe unexplored. Anyone got any recommendations on lay-person books on sleep/subconscious?