Margaret Thatcher declared she could get by on far less of it than the rest of us; Thomas Edison regarded it as a waste of time; and Janis Joplin tried to avoid it when possible, on the grounds that she might miss a good party.
But according to the latest research, most of us just aren't getting enough sleep for our own good. In the highly competitive consumer societies of the US and Western Europe, sleep is now regarded as something of a necessary evil - if you want to get on, you certainly don't get under the bedclothes. Since the invention of the electric lightbulb in 1879, "daytime" activity is no longer limited by natural light. Sleep patterns began to change, and over the next century we reduced our average total nightly sleep time by 20 per cent to eight hours a night, which is what most of us fondly imagine is more than enough to keep us going. But here's the bad news. In 1995 a Gallup poll in the US found that many people routinely get just seven hours' sleep a night, while one-third of the population now spends less than six hours a night asleep. The same study concluded that the average American has added 158 hours to his or her annual working and commuting time over the last 20 years. So, not only are many of us actually getting less sleep than we imagine is enough - but enough, says Dr James B. Maas in his newly-published book Miracle Sleep Cure: The Key To A Long Life Of Peak Performance, is not, in any case, anywhere near enough. Maas, a sleep researcher and psychology professor at Cornell University, reckons that in order to function properly, the average working adult needs 10 hours of shut-eye, which means that at least 50 per cent of the adult population of the industrialised world - and that means either you or me, pal - is chronically sleep-deprived. The symptoms are not pretty. Lack of sleep doesn't just make you tetchy, lethargic and prone to mood swings; it also slows reflexes and lowers your body's immune responses. Prolonged lack of sleep will produce hallucinations and paranoid delusions. Eventually, a life will be in danger - if not your own, somebody else's, says Maas, who has a fistful of horror stories to prove his point. Like the comment of Eastern Airlines captain, James Reeves, to the control tower half an hour before he crashed his plane at low altitude in September 1974, killing himself, the rest of the crew and all 68 passengers: "Rest," Reeves apparently complained. "That's what I need, is rest . . . " Or the harried young computer programmer who forgot to drop his five-month-old son off at the babysitter's on his way to work; the baby was found that evening, still strapped in his seat in an overheated car, his body temperature still at 106F even though he had been dead for some time. The father was described by a colleague as "a dedicated employee who put in a lot of extra hours, and had probably overworked himself that week to the point of distraction". OK, OK, we get the picture - but how do we know if we're chronically sleep deprived? If, as you read this, you're silently congratulating yourself because you fall asleep the minute your head touches the pillow, or the instant you get into an aeroplane, you're in for some more bad news.
"This is a sure indication of sleep deprivation," says Maas sternly. "The well-rested person takes 15 to 20 minutes to fall asleep. Think how ridiculous it would sound to brag about being a good eater because you devour meals the instant they are put in front of you . . . "
In order to take your first step towards a long life of peak performance, he declares, first you need to understand exactly why sleep is so important. It's not just a matter of lying down with your eyes closed - on the contrary, the various stages of sleep are characterised by significant changes in brain waves, body temperature, muscle activity, respiration, hormonal activity and genital arousal.
The various activities of the "sleeping" brain play a dramatic role in regulating gastrointestinal, cardiovascular and immune functions, in energising the body and in cognitive processing - the organisation, storage and eventual retrieval of information already in the brain. In many ways, concludes Maas, the "sleeping" brain is actually more active than the "awake" brain. Next you need to work out your own personal nightly sleep requirement, essentially by juggling your bedtime for a week and monitoring the results. And then you have to stick to it religiously, pay back any "sleep debts" you may incur as soon as possible, and maintain regular sleeping patterns at all times - no burning the candle at both ends during the week and then sleeping all weekend, mind.
Maas offers a selection of sleeping "do's" and "don'ts", some more appealing than others ("avoid chocolate and high-sugar foods near bedtime . . . satisfying sexual activity can promote sleep onset and induce deep and restful sleep") rhapsodises about the benefits of a natural-fill pillow and has a few words for stressedout shift workers and parents of small children. So enthusiastic is this man about the benefits of sleep that it's hard to resist putting his book down in order to nap between chapters (yes, that's the ticket, says Maas; any day now, napping will have the same status around the office as a daily workout). In order to benefit fully from his theories, you'd need to be blessed with the sort of boss who wouldn't turn a hair if you turned up for work in mid-afternoon. And if you had a serious sleep disorder it's unlikely that his jolly-hockeysticks opinions on mattresses and natural tranquilisers would help much.
But when you get down to it, what he's actually saying is that if you sleep for just an hour longer every night, you'll feel better, work better, play harder and live . . . oh, is that the time? Sorry, folks, gotta go; it's way past my bedtime.
Miracle Sleep Cure: The Key To A Long Life Of Peak Performance, by James B. Maas, is published by Thorsons at £7.99 in UK.