A Life in Progress : Some of us don’t get it. But Gail Sheehy does. In ‘New Passages,’ she shows how we’re redefining the concept of ‘aging.’

You have to admire a woman who spent seven years writing a book that’s meant to be educational, uplifting and illuminational--if that’s a word.

And if it isn’t, who cares?

Not Gail Sheehy.

In “New Passages,” just released by Random House, the author invents not just new words ( middlescence ) but new phrases (“the aha moment”) and new life stages (Provisional Adulthood, Second Adulthood), even whole new “bonus decades” of existence--in fact, an entire glossary of neologisms to describe the ever-expanding stages of our lives, most of which might be distilled by less creative minds into that old cliche: “We’re not getting older, we’re getting better.”

At 57, Sheehy is truly trim. Not a parched or starved Size 6, but hard-bodied and muscular--a person who takes boxing lessons to keep her knees in shape “so I’ll be able to jog in the early morning when I’m 80, just as I do now.”

This is good. She takes her own advice.

While traversing her “Flaming 50s” (during which today’s women are “more fulfilled and enjoy greater well-being than at any other stage of their lives”), she prepares for her “Serene 60s,” which includes the “Age of Mastery” (45 to 65) and “The Age of Integrity” (65 to 85-plus) . . . and for heaven-knows-how-many lusty adventures of the heart that were not available to our parents and grandparents because they felt old at an age when we are just starting to feel in control of our lives.

In fact, in 1976 when Sheehy’s first blockbuster book, “Passages,” was published, the author recalls that she then “viewed the mid-30s as the halfway point in life, and the years between 35 and 45 as ‘the deadline decade’--a time to resolve the crises of midlife.”

Her discussion of life cycles in that early book stopped before the age of 50, she says, because by that time most people’s children had been launched, careers had been settled, and “anything beyond that age was a time of winding down, when people coasted on successes and resigned themselves to failures, when idealism had faded, learning was completed, and love was no longer about physical sex.”

Now, just 20 years later, she says, revolution has occurred.

In the space of a single generation, the fundamental cycles have shifted. Adolescence and partial dependence on family lingers until the late 20s. True adulthood doesn’t begin until 30, she says.

Thirty is what 20 once was; 40 is what 30 used to be; 50 is just the beginning of what, in essence, is an entire second life to be lived for millions who will remain productive, energetic and enthusiastic for perhaps another 40 years. (Don’t laugh. A woman who reaches 50 and remains free of cancer and heart disease can expect to see her 92nd birthday, Sheehy writes. And a healthy man of 65 can expect to live into his 80s.)

What will we do with what amounts, for many of us, to an entire second lifetime?

Remake ourselves, of course, starting with “middlescence”--a precursor to the passage into midlife that occurs between 45 to 55.

Nowadays, Sheehy says, many people in their 40s have their first babies and family experiences, or they start second families. Whatever they do, “These people have no concept that they are entering middle age--and they aren’t. Because that set of stereotypes doesn’t apply anymore,” Sheehy says.

“In terms of work, the whole concept of retirement has to be totally redefined. We may leave the careers of our first adulthood,” and embark upon new ones “more customized.”

*

Sheehy is remaking herself even now, as she entertains a reporter on the fern-filled patio of her Bel-Air hotel room, the sun glistening on her softly curled, copper-colored hair. In Los Angeles last week to promote her just-released book, she seems mindful of the many career miles she has yet to go.

Each time the phone rings (which is frequent) she hops to it, then reports to the reporter. As in: “It’s Brandon Tartikoff, and I must talk to him because we’re trying to do a documentary.”

In a quiet moment, she admits that “the 50s may be my personal obsession, because that’s where I am in my own life. But it seems to me that this is where the greatest explosion of new life, of unmapped territory, is. This vast ‘thing’ has opened up in the middle of life that wasn’t ever there before.”

Today, she says, the 50s and 60s are an “optimistic, can-do stage of life. You have found your own voice, you have moved away from wanting to please parents, bosses, all sorts of others, into a phase of wanting to master your own personal goals.”

Her major recommendation for people entering Second Adulthood is to “find your passion and pursue it.”

This takes guts. And in Sheehy’s case, it turns out, it also takes a change of residence, from East Coast to West, to accommodate her husband’s later-life ambition.

A magazine editor for most of his life, Clay Felker, nearing 70, realized that he was “no longer in a position to continue editing new magazines,” Sheehy says. “So we spent two years figuring out what it was about being an editor that he loved so much, that was really his passion. We found that it was identifying and shaping young talent.”

Felker transferred that talent to UC Berkeley, where in September he’ll inaugurate the Felker Center for Magazine Journalism, at the graduate school of journalism.

Sheehy will be with him, of course. And for both, academia will be a far cry from the heady neo-literary life of their Gotham heydays, when Felker, Sheehy and New York magazine were trendy names to drop.

*

Sheehy was born in the upscale Manhattan suburb of Mamaroneck, graduated from the University of Vermont, worked briefly as a traveling home economist for JCPenney, married medical student Albert Sheehy and gave birth to a girl. End of life cycle 1.

Then she discovered her true passion--journalis--and began a series of newspaper jobs that landed her at the now-defunct New York Herald Tribune from 1963 to 1966. It was a time when Felker (described by colleagues as a lanky cross between Robert Mitchum and John Wayne) was editing the paper’s Sunday supplement magazine, called New York.

Felker was married to actress Pamela Tiffin; Sheehy was the internist’s wife.

Soon each was divorced and the newspaper had folded.

But Felker kept the supplement alive as an independent magazine, which became the first, the best and the prototype for the slew of city magazines that have since sprouted across the world.

Under his founding editorship, New York magazine soared, with innovative graphics by Milton Glaser and the introduction of New Journalism, as practiced by the likes of Tom Wolfe, Peter Maas and, yes, Gail Sheehy--all talents fostered by Felker.

The prolific Sheehy, whose name was unceasingly splashed in big print across the magazine’s cover, was not just a journalistic find for her boss; she was his inamorata in a romantic liaison.

“I was beginning to find my writing stride,” Sheehy recalls, her expression growing animated. “Clay challenged me, he pushed me, he began sending me around the world on assignments. He recommended me for a fellowship at Columbia, which is where I studied under Margaret Mead and found that anthropology was my kind of journalistic direction. We had a wonderful, exciting, tempestuous relationship that never resolved itself in marriage until about 12 years later.”

After Sheehy’s daughter went off to college, Sheehy says, she told Felker that she felt she hadn’t yet completed her family. “I wanted another child. In fact, I longed for that.” Felker, who had no children from previous marriages, “resisted the idea.”

The couple was traveling in Asia, she recalls, sitting on the veranda of a posh hotel “under the most sybaritic circumstances you could imagine,” when “Clay picks up the Bangkok Post and shows me a story about orphans and suggests maybe I ought to adopt one. It was just like everything else with us,” she says with a loving laugh. “He actually put me up to it. Then I did it. Then he said, ‘you’re crazy.’ ”

Sheehy adopted Mohm, 12, who had survived unspeakable wartime horrors and “had never had a childhood.” Mother and child were “joined at the hip” for the first two years, Sheehy says, during which time the girl “learned English, learned what it meant to be American, and learned to accept Clay. That was the biggest hurdle because she didn’t want him to come between the two of us.”

When Felker and Sheehy married 10 years ago, they began what Sheehy calls “the best years of our lives. Clay rebuilt his New York apartment and we moved in together and we were just this little family, sitting and talking together for hours about everything in the world. Clay became a father for the first time. I mean, Mohm really is his child, just as much as if she were born to him.”

*

Although she has written 12 books, Sheehy’s fame came with “Passages,” which was succeeded by “The Silent Passage,” a book about menopause for which she says she unwittingly became “the poster girl.”

With this new book, it seems clear that she’s still in form--and still controversial. The New York Times reviewer liked it; the Washington Post reviewer didn’t, saying it gave her nightmares.

Criticism doesn’t faze Sheehy. Her recipe for happiness is to be “never short of a dream, to always have another vista that you’re aiming for. So when you shuffle off this mortal coil, your life-in-progress will be an unfinished work because there’s always more you might have done that you wanted to do.”