Sleep

A friend of mine has an anesthetist in the family and I've been thinking about sleep for months now. What is physical sleep, what is being put to sleep, and to me, there is a very fuzzy line between anesthesiology and psychology, and perhaps neurology. And hypnosis? I'm very interested, but I don't want to be bogged down in learning the -ologies and new vocabulary at this time. Time to add to the bottom of my list.