Fra begyndelsen af artiklen: Did our forefathers ever sleep? They must have done, sleep being an elementary body function. But sleep displays cultural variations and has cultural meaning as well. Sleep is staged with different artifacts, rooms and by different performances, culturally informed and individually decided. Like eating, dressing and housing, sleeping is a common human feature. Modern science tells us that we sleep at least 1/3 of our lives. A life of 70 years includes about 23 years sleeping and dreaming. Modern science also informs us that there are four periods of sleep interrupted by REM (Rapid Eye Movement) sleep, when we dream. Of the 23 years of sleep we might dream during as many as five or six of them. We remember very little of this (Alvarez 1995: 84).