Prior to a light bulb, the 19th century people slept about 10 hours. Before we began using the fire and candles, and probably more. Today the average person sleeps 8 hours a day. Due to the fact that we have more in front of the computer, but in bed during sleep is significantly shortened. Once people thought, believed in her dreams and read “Dream interpreter”… Oh, there is less of such books, because there is less dreams. We may soon, like dolphins sleep with one eye open.