Economic globalization obviously has a great deal to do with the change of prolonged working hours. It has leveled the playing field all over the world, so that the have-nots can now compete more equally with the haves, especially if they are willing to work harder, longer and for lower wages, which so many of them are. And the haves, in turn, find that they have to pick up the pace just to stay even. But there may be a more insidious force manifesting itself—something along the lines of an evolutionary law that says, paradoxically, the more you try to simplify or eliminate work, the more of it there is to do. Scholars estimate that medieval peasants, for example, worked between 120 and 150 days a year. They didn't have holidays as we understand them, but they had about eight weeks' worth of holy days, which amounted to the same thing. The notion of a regular workweek was a late-18th-century invention, a product of the vastly speeded-up pace of the Industrial Revolution, which instead of liberating workers, virtually enslaved them, dooming entire families to numbing stretches in what Blake called the'dark, Satanic mills. 'The Mills and Factories Act, passed in England in 1833 to curb the worst labor abuses of the time, limited children 9 and older to 48 hours of work a week and teenagers to 69 hours. Adults worked even longer, and they did so in part simply because they could. The Nobel Prize-winning economic historian Robert William Fogel has studied what he calls the'efficiency of the human engine'and found that the mechanical advances of the Industrial Revolution were paralleled by an equal increase in the human body's size, strength and endurance. In his view the great growth industry of the 19th and 20th centuries was the capacity for work itself. The more work we do, apparently, the more we're able to do, and though Fogel himself takes a sort of Toffler-like view of the 21 st century, predicting that leisure will become the next great growth industry, there's little evidence of that right now. Working hours in America—the nation in the world with by far the most efficient human engines—have risen steadily over the last three decades. And far from complaining, we have adopted a superior, moralizing attitude that sees work not as a necessary evil, a means to an end, but as an end in itself. It is now obligatory to boast—to lie, if necessary—about how much you work and how little you sleep. The Stakhanov for our time is that lawyer who a few years ago billed 62 hours over a 24-hour period. Most everyone now faces the dismaying prospect of falling by the evolutionary wayside, a casualty in the global rat race. Unless we can be chemically or behaviorally enhanced, that is, and for those whose work ethic is faltering, there is some encouraging news. Provigil, a drug for narcoleptics, has been tested on Army helicopter pilots, who found that it enabled them to stay awake and alert for two days straight. And the Defense Advanced Research Projects Agency is working on programs to modify the metabolism of soldiers so that they can will themselves not to bleed and can function efficiently without food or sleep for up to a week. They might even be able to survive without oxygen for a brief while. This is something the French would never think of. According to Robert William Fogel's theory, _____.