SO MUCH to do, so little time. Between a hectic work schedule and a thriving social life, Yves (not his real name), a 31- year-old software developer from Seattle, often doesn’t have time for a full night’s sleep. So he swallows something to make sure he doesn’t need one. “If I take a dose just before I go to bed, I can wake up after 4 or 5 hours and feel refreshed,” he says. “The alarm goes off and I’m like, let’s go!”

Yves is talking about modafinil, a stimulant that since its launch seven years ago has acquired a near-mythical reputation for wiring you awake without the jitters, euphoria and eventual crash that come after caffeine or amphetamines. Yves has been popping modafinil on and off for the past three years and says it is “tremendously useful”. “I find I can be very productive at work,” he says. “I’m more organised and more motivated. And it means I can go out partying on a Friday night and still go skiing early on Saturday morning.”

Modafinil is just the first of a wave of new lifestyle drugs that promise to do for sleep what the contraceptive pill did for sex – unshackle it from nature. Since time immemorial, humans have structured their lives around sleep. In the near future, we will, for the first time, be able to significantly structure the way we sleep to suit our lifestyles.

“The more we understand about the body’s 24-hour clock the more we will be able to override it,” says Russell Foster, a circadian biologist at Imperial College London. “In 10 to 20 years we’ll be able to pharmacologically turn …