Recently I got a book called Powerful Sleep. It is very interesting and I recommend it to anybody. It starts with some theory on sleep, and goes on to explaining how the internal clock works, how body temperature is related to the pattersn of feeling sleepy, also talks about the importanc of sunlight and water. In few words, to increase the quality of your sleep and decrease the amount you sleep you should: Get up the moment you wake up and get some sunlight in your eyes. Don’t drink cofee, take a short ( not more than 40 minutes ) nap once a day in the time you feel most tired, and don’t eaty heavy food at night. Also, avoid doing things in bed other then sleeping and sex. Try to sleep in as dark as possible and get as much sunlight as possible during the day.
Highly recommended.