If anyone is interested in this topic, check out the book "The Promise of Sleep". It's the story of one of the earliest sleep researcher (before we knew about REM) and his journey into understanding sleep.
It some interesting insights into sleep, for example why it's better to be a little tired than overslept.
It some interesting insights into sleep, for example why it's better to be a little tired than overslept.
http://www.amazon.com/Promise-Sleep-Medicine-Connection-Happ...