The specter of aging is ominous: wrinkles, memory loss, mortality. But fears of the inevitable can obscure the upside of getting older: being at the top of your game. As baby boomers age, many of them are realizing that life after retirement is not merely a long, slow decline. There is still wisdom to be gained, work to be done and adventure to be had.

Plenty of people thrive in their professions long after their cohorts have retired. Placido Domingo, 69, is still conducting, singing and directing two major operas. Lyudmila M. Alexeyeva, an 82-year-old Russian activist, has been arrested for organizing protests so many times in the last 43 years that she is an expert at provoking and pestering the K.G.B. And Anthony Mancinelli, 98, was declared the world’s oldest barber by the Guiness Book of World Records - and he still cuts his own hair, Vincent M. Malozzi reported in The Times.

“I’m not even considering retirement,” Mr. Mancinelli told The Times, “because coming to work is what keeps me going.”

Work keeps many baby boomers going. Some workers 55 and older are even seeking out new careers.

Janet Mitchell of Leo, Indiana, trains social workers, ministers and others to mediate family conflicts. “About half are baby boomers with aging parents,” she told Elizabeth Pope of The Times. “Younger people might not have the credibility to do this job.”

Others are taking decades worth of skills and contacts and striking out on their own. The number of selfemployed Americans ages 55 to 64 climbed 52 percent from 2000 to 2007, according to the federal Small Business Administration. Cinde Dolphin started her own marketing firm at 55 . “I’m having a ball,” she told The Times. “I can set up my own hours and work schedule, and do other things I enjoy.”

New research shows the mind keeps developing into late adulthood. “The brain, as it traverses middle age, gets better at recognizing the central idea, the big picture,” Barbara Strauch wrote in The Times. “If kept in good shape, the brain can continue to build pathways that help its owner recognize patterns and, as a consequence, see significance and even solutions much faster than a young person can.”

Another benefit of the leisure years is having time to travel. Retirees are getting more adventurous, climbing Mount Everest, hiking the Inca trail or even wing-walking.

“This is an emerging market phenomenon based on tens of millions of longer-lived men and women with more youth vitality than ever imagined,” Ken Dychtwald, a psychologist and author who has written widely about aging, told Kirk Johnson of The Times.

Even in the nursing home, sympathy can be misguided, Dr. Marc E. Agronin, a psychiatrist, wrote in the Times. “It stems in part from an age-centered perspective,” he wrote, “in which we view our own age as the most normal of times, the way all life should be. At 18 the 50-year-olds may seem ancient, but at 50 we are apt to say the same about the 80-year-olds.”

And as for the 100-year-olds?

“I forgot I was so old,” a centenarian patient told Dr. Agronin. Then she headed off to her bingo game.


KATHLYN HOTYNSKI


Placido Domingo, at the age of 69, is still conducting, singing and directing two major operas. / SARA KRULWICH/THE NEW YORK TIMES