Most of us believe that we sleep in order to rest our tired bodies and minds. Originally published in 1977, this centuries-old common-sense view is challenged by Ray Meddis, who describes and argues for a controversial new theory of the nature and function of sleep. The theory seeks to replace the old view with the idea that sleep may no longer serve any important function in modern man. Whereas the sleep instinct helps animals to survive by driving them to hide away for as long as possible each day, this is no longer a valuable asset in civilised surroundings. Nevertheless, as the author explains, we still feel driven by a primeval urge beyond conscious control to crawl away every evening to the security of our beds to wait out the dangerous hours of darkness which were such a threat to our ancestors. Contrary to contemporary wisdom, he also argues that dreaming is a primitive and particularly valueless kind of sleep – a crude a dangerous heritage from our reptilian ancestors which is kept to a bare minimum in most adult warm-blooded creatures. Ray Meddis writes in a non-technical style and succeeds admirably in making the science of sleep and intensive research studies on sleep accessible and even exciting for the general reader as well as for the scientist. He shows that not everyone is bound by a felt need for sleep; in fact, some human beings discussed at length in the book thrive on less than two hours sleep a night without any ill effects. The implications of the research described are little short of sensational; in particular, Dr Meddis believes that it is well within the bounds of possibility that future research will show us how changes can be brought about in normal people to free them from the bondage of their sleep instincts. This new perspective also leads directly into a radical reappraisal of the nature of insomnia and new possibilities for treatment.