If one place on earth has vanquished nature and stopped the clocks, it is Las Vegas. Built on land without

water or any reliable resource apart from the blazing sun, the resort entombs visitors in the permanent,

cool, jangling dusk of hotel casinos. Its skyscape positions ancient Egypt near Renaissance Venice and

fin de siècle Paris. I had come to this confected city to find out if the Cenegenics Medical Institute, "the

world's largest age-management practice," could subvert the laws of human biology with similar ease.

First I had to locate Cenegenics, and though you might think it would be easy to spot a building described

by its tenants as "quite a lot like the White House," the cab driver took more than a few passes before we

were able to pick out the right White House from the rows of White Houses that have sprouted in the

Nevada desert.

That's the Vegas paradox: despite the mind-boggling range of architectural styles and eras represented,

there's a remarkable uniformity to it all. The residents are similarly homogeneous. Perma-tanned and

toned, many of them sport a uniface common to both genders and across the income range, from

bellhops to casino owners. The uniface is defined by absences: its eyebrows have been plucked,

threaded or waxed into submission; its fine little nose is free from bumps and bulges. Above all, it looks

neither young nor old. It is ageless. It is amortal.

Amortality — the term I coined for the burgeoning trend of living agelessly — is a product of the world

many of us now inhabit, a sprawl of virtual Las Vegases, devoid of history and shorn of landmarks that

might provide guidelines for what is expected of us as the years pass. Youth used to be our last hurrah

before the onset of maturity and eventual dotage, each milestone — childhood, adolescence, young

adulthood, middle age, retirement, golden years, decline — benchmarked against a series of culturally

determined ideals. But as our life spans have lengthened — across the developed world, we are now

living 30 years longer than we were at the beginning of the 20th century — the ages of man have started

to elide. If you doubt that statement, think how hard it is to answer the following questions: What's the best age to have children? Or to settle down with a life partner? Or to retire? When might a woman

consider herself middle-aged — at 40, 50, 60? Does that differ for a man?

The meaning of age has become elusive, visual clues untrustworthy. Children dress like louche adults.

Their parents slouch around in hoodies and sneakers. Rising phalanxes of Dorian Grays rely on exercise,

diet and cosmetic procedures to remain transcendentally youthful, while glowing teens and

20-somethings are propelled by some of those same procedures into a semblance of premature aging.

The rules of age-appropriate behavior that used to be reliably drummed into us by parents and teachers,

church and state, no longer hold sway. But we haven't lost faith; we've just transferred it, to scientists and

celebrities. Hollywood is the home of amortality, the music industry its outreach program. "I think you

should just keep going while you can, doing what you like," Mick Jagger observed at 66, ignoring his

pronouncement in May 1975 that he'd rather be dead than be singing "Satisfaction" at — or presumably

long after — 45.

Doing what you like might include adopting children at 49 and 50, like Madonna; becoming a first-time

dad at 62, like Elton John; preparing to marry a woman 60 years younger than yourself, like Hugh Hefner;

or, like Jagger himself, reversing the traditional order of marriage and bachelorhood. These are amortal

choices. But amortality is not invariably synonymous with extended youth. Meryl Streep represents a

different expression of amortality, a true agelessness. And Woody Allen exhibits one of the classic

symptoms of amortality, constructing a personal and professional life full of distractions. He never rests.

He has turned out at least one film a year for all but three of the last 40 years and performs regularly with

a jazz band. As he told an interviewer, "When you're worried about this joke, and this costume, and this

wig, and that location and the dailies, you're not worried about death and the brevity of life."

The defining characteristic of amortals is that they live the same way, at the same pitch, doing and

consuming much the same things, from their late teens right up until death. They rarely ask themselves if

their behavior is age-appropriate, because that concept has little meaning for them. They don't structure

their lives around the inevitability of death, because they prefer to ignore it. Instead, they continue to

chase aspirations and covet new goods and services. Amortals assume all options are always open.

They postpone retirement by choice, not just necessity; one of the reasons the American Association of

Retired Persons changed its name to AARP was that many in its demographic were, in fact, still working.

And they're having children later than ever — and often relying on fertility treatments to do so.

A by-product of prosperity, amortality influences behaviors across the socio-economic spectrum and from

youth to old age. But as amortals get older without "getting old," they become more conspicuous.

Upturning conventions of aging isn't necessarily a bad thing, given the maturing profile of the world's

population. By 2050, more than a fifth of humanity will be 60 or older, and in the U.S., the 60-pluses will

make up 27% of the population. The amortal impulse to stay active, if properly directed, could help ease

the anticipated labor shortage and curb swelling health care costs, but amortality is not without its risks.

Amortals have a dangerous habit of trusting that science will be able to deliver them from the

consequences of aging or, at a minimum, allow them to select the timing and manner of their passing if

the range of products and programs promising to preserve us should fail.Gains in longevity have been achieved by eliminating or neutralizing many threats to our lives, but the

main threat — aging — has proved more resistant to intervention. In 1961 a microbiologist called

Leonard Hayflick made a depressing discovery. He found that most human cells are able to divide only a

limited number of times, so that even if we get through life without contracting a single disease, we'll die

when enough of our cells cease dividing. Although our life expectancy continues to increase, by two to

five years per decade in the developed world, the Hayflick limit would appear to doom us to a maximum

of around 120 years.

But that doesn't stop amortals from aspiring to spend as long in their bodies as possible. There's a

thriving specialist health care sector promising to help us do so, and Las Vegas is one of its hubs.