A number of years ago, Donald Keough, president of Coca-Cola, retired. At 66, this garrulous, hard-charging, oft-described “people person” executive was reluctant to leave, but he had reached the mandatory retirement age. Most of his friends and colleagues, as would be expected, thought he would walk into the sunset with his pockets full of cash to enjoy devoted family time. He would lead the retirement life so many people dream about—rich, abundant in energy, and free of worries. So, on a cool Friday morning in Spring, Don packed up his office, bade goodbye to his colleagues, and made his graceful exit.

But by Monday, much to the surprise of his friends, Don flew to New York to take a job chairing a boutique investment bank called Allen & Co. “Don, what are you doing?” his friends asked, perplexed. Don was a man with many millions of dollars who could do anything he wanted—join some boards, travel the world, and build his dream house or houses. But Don wanted to work again. Hard work. “You’ve been working all your life,” another friend declared, who seemed more puzzled by the move than happy for him. “Why don’t you relax for a bit and then jump back in?”

“You kidding?” Don replied to each of the inquiring friends.

“I’d end up like those guys in pink pants.” As Don later told us when we interviewed him, he’d been vacationing for many years at an exclusive coastal golf resort. The place was Palm Springs meets Southern hospitality. Most people were retirees from the upper echelons of society, spending their days enjoying the beaches and golf courses, dining at worldfamous restaurants, and driving their yachts out onto the sapphire-blue water. To you and me, it would be Retiree Utopia.

But for Don, it was Retiree Prison.

Over the years, he’d begun to realize this happy place was inhabited by some unhappy people. Every time he visited, invariably one or two friends or acquaintances would tug at his sleeve and take him aside. “Don,” they’d breathe. “What’s it like out there in the real world?”

“What do you mean?”

“You know, the real world. The place where things happen, where you’ve got a place to be, people to meet. I’m going crazy here with all this time on my hands. I never thought I’d say it, but I need to get away from this.” This, of course, meaning a permanent “dream” retirement.

The one thing Don noticed about these people was that many of them wore pink pants. Or pink shorts. Some pants were more of a pastel pink. Others wore salmon-colored pants. One sported generous flamingo pink neon. “There’s something about when you go into retirement and spend a few years in that phase of life, that suddenly all these perfectly well-dressed men start wearing these God-awful pink pants. I said to myself, I said to my wife, I will never be caught dead in those damn pink pants.”

That was how Don decided his second act was going to be as far away from the golf resort as possible. At 79, he’s as energetic as ever, jetting across the globe to meetings, overseeing corporate mergers that you and I have probably read about in the newspapers, and mentoring the next generation of corporate leaders and CEOs. Rather than pink pants, he has stayed in his favorite business suits.

Don’s story describes a lot of what this book is about. It’s about throwing out all conceptions about the traditional retirement years. It’s about defying the conventions that say aging means a bland, low-excitement life. It’s about how to prepare now—financially, physically, mentally—for your second or even third act.

It’s about saying no to wearing pink pants.

When most of us think of aging, we think of our body and health and our retirement. We worry about whether we are taking care of our bodies. Are we eating the right foods? Are we exercising enough? Are we going to develop crow’s feet or age spots? We also worry if we’re socking enough money away for the post-65 retirement period. Do we have enough to sustain our way of life for the next 20 or 30 years? How much should we save? What are the best retirement accounts?

When it comes to aging well, most of the books and magazine articles focus on getting these two areas on track—health and retirement. They should—these areas are of utmost importance as we look toward our future. But they’re not the only things we should look at when we think of aging well.

We don’t often think about whether having an unhappy marriage is cutting our lives short. Or whether the stress we feel from work is slowly making us susceptible to heart disease, cancer, and other chronic diseases (not to mention adding plenty of wrinkles and bags under the eyes). Or that staying curious is one way to exercise the mind, protecting against Alzheimer’s and other forms of dementia.

When Jean Calment died in Arles, France at the age of 122, she became the longest living human being on record. Over the years of her life, scientists discussed her diet and her exercise routine, observed her living conditions, and recorded her mental acuity. But rarely did anyone talk about her great sense of humor. Ms. Calment once told a story about a lawyer who signed her up for a pension scheme that gave her monthly payments in exchange for the ownership of her apartment. Being that Ms. Calment was already 90 back in 1965, it appeared the deal was a win for the lawyer—he’d only have to make a few payments before she died and the company could seize ownership. But not only did Ms. Calment live for another 32 years, she also outlived the lawyer and received payments worth three times the value of her apartment! To which the French lady quipped once, “We all make bad deals in life.” In another story, a reporter said at Ms. Calment’s 120th birthday party that he’d “see her next year,” eliciting the feisty centenarian to reply, “I don’t see why not. You look to be in pretty good health to me!”

Ms. Calment’s sense of humor was likely an important factor in her living to 122, just as what she ate or how much she exercised. But you never hear much about that.

Things that have a clear cause-effect relationship are easy to understand. If you smoke, you can get lung cancer. If you eat too many French fries, you’ll likely get fat. If you don’t save at least 10 percent of your paychecks, you’ll be less prepared for retirement.

How do you evaluate the concrete health benefits of being able to see the funny things in life, as Ms. Calment could? Or being religious? Or being a happy person? Or having a happy marriage? It’s not as if you can say, “Laugh three times a day to lessen your chance of heart disease.”

Thankfully, an increasing amount of research is devoted to just these topics, melding the fields of psychology, neurology, epidemiology, and sociology. Some have pinpointed how many years an unhappy marriage might lop off your life, or exactly what happens to people biologically after they’ve attended church regularly. We present some of the most exciting research in this book, along with interviews from some of the leading doctors around the country.

Science is sort of playing catch-up because in many ways, there are millions of people in this country who are aging well and practicing the “aging secrets” that are just now being corroborated by research. People who’ve reached their 70s, 80s, and 90s intrinsically know what’s made them live so long—and it’s not just about diet and exercise. Phil Mazzilli, a vibrant 95-year-old retired property assessor who worked up until two years ago, confesses his diet for his whole life has been “off color.” Instead, he attributes his long life to not letting stress wear him out. “I never ate greens. I didn’t like salads. My favorite meal was sausage with a pepper wedge,” he admits. “People who have stomach troubles, it’s not from what you eat, it’s from your nerves. Everything reacts to nerves. You worry about this or that, worry about not doing anything right, that’ll get you. As it stands now, I’ve done very well for myself; I’m content and satisfied. When I go, I go. I’m not going to worry about it.”

Aging well is a central issue right now because for the first time in all of humanity, a majority of people on average will live to old ages. We talk more about life expectancies and the Baby Boomer generation later in the book, but just think that only a mere 100 years ago, most Americans could expect to live only until their 40s. That doesn’t mean there weren’t elderly people in previous generations—George Washington lived to the ripe old age of 67, outlasting a typical American man of his time by about 15 years. But average Americans had a short, often hard life. Then with better sanitation, the development of vaccines and antibiotics, and improved living conditions, Americans suddenly saw their life expectancies jump as babies stopped dying shortly after birth. Improving medical care and health prevention measures—like raising public awareness about the dangers of smoking and not wearing seat belts—lifted life expectancies from birth even further in 2003 to 75 years for men and to 80 years for women.

We’re cresting right now. Any further gains we make in extending our lives are going to come either out of someone’s genetic lab or out of us practicing a better lifestyle. Being that any miracle life-extending drugs are probably decades, if not centuries, away, aging well now is a matter of doing a bunch of things that add up to the one big thing: a long and healthy life.

Even people on the cutting edge of longevity research know that for now, aging well is a matter of practicing simple habits, such as getting enough sleep, keeping stress down, and having good, strong relationships. Jonathan Fleming, one of the country’s leading biotechnology venture capitalists, recognizes that with all the money poured into genetic research, with grand plans of finding the magic life-extending gene or genes, one of the greatest inventions in recent years to lengthen people’s lives boils down to something as basic as an artificial joint. Fleming says:

"This has been a revolution [in longevity] because the biggest risk to mortality as you age is falling. If you fall and break your hip, you can get complications from a broken hip and that can lead to death. Now you’ve got grandmas living to be 90 years old with robot parts in them. It’s incredible. It’s the shift that makes it possible for your golden years to be 30 years long."