Mark Walton was in his late 20s when he became the first White House correspondent for the fledgling CNN. He won a Peabody award as a foreign correspondent in his 30s, and in his 40s, successfully transitioned to a new career as head of an executive development company.

In his mid-50s, Walton found he couldn't sleep at night, haunted by two simple words: What now?

"The idea of having 30 years to go -- knowing I was capable of doing something else and not knowing what it was -- I found terribly disturbing," said Walton, chairman of the Center for Leadership Communication. "Then I started hearing from other folks my age and older who felt the same way." That motivated Walton to begin exploring the possibilities, and seeking out lessons from people who pulled off major reinventions in their 50s and 60s.

The result is "Boundless Potential" published in March. In the book, Walton profiles a diverse group of people who launched remarkable second acts; explains why everyone in their 50s should be prepared for difficult change; and offers a three-step blueprint for reinvention, based on the life experiences of the people interviewed.

They include Sherwin "Shep" Nuland, a retired surgeon turned best-selling author; Marion Rosen, a physical therapist who pioneered new techniques in her 60s and developed an institute that established her "Rosen Method" in training centers worldwide; and Gil Garcetti, the L.A. district attorney who failed to get a conviction in the O.J. Simpson trial. He became a world-class photographer and activist, raising funds to bring clean water to West Africa.

While most 20th century workers were engaged in physical labor, most baby boomers today are "knowledge workers," said Walton. "My parents were happy to retire at the prescribed age," he said. "It's the boomers, for whom work has been central, who are reinventing themselves. They have the next 20 to 30 years of their lives and they're saying they still want to do something meaningful."

As Dr. Nuland noted in his interview with Walton:

"Why is the idea of retirement so powerful? I think because people look forward to it for so many years. But they don't know until they get into it that it has distorted their lives and sent them off on a tangent that is not the continuation of what they have always been."

"Boundless Potential" also covers a decade of research in neuroscience that indicates the brain "is hard-wired for reinvention" as Walton puts it. "The mind doesn't burn out. Neuroscientists over the last decade have done work that has found the mature brain is organized differently than the younger brain, and when it's adequately challenged, it keeps growing."

In fact, post 50s have an advantage over their younger counterparts, Walton argues. Though the brain may lose some of its processing speed and accuracy over time, years of using their skills and talents, social and emotional skills, and creativity coalesce in what Walton calls "crystallized intelligence." It's the cognitive ability to make wise decisions under pressure, Walton explains.

One example is Chesley "Sully" Sullenberger III, who at age 57 made the split-second decision to land his disabled plane safely in the Hudson River in 2009. "What Sully experienced in that split second was only likely scenario to save the plane, and a younger guy with less experience wouldn't have been able to do that in the same time," Walton argues.

"We speak of 'experience' as though it's nothing and it's dismissed in the workforce -- but part of wisdom is cognitive templates, or changes in the brain," Walton said.

"The human brain was never designed for decline or retirement, but for continual reinvention. The mature brain is organized differently than the younger brain, and when it's adequately challenged, it keeps growing and developing."

Unfortunately, not all employers value that wisdom, and reinvention can be forced upon people who find themselves replaced by younger, cheaper labor. "We talk lightly about reinvention in this culture right now and the reality is it's very hard work and takes a lot of gumption," said Walton. "You have to create a support system for yourself because it's tough to do. It's like being an entrepreneur; you'll get knocked down and you'll have to get up again."

Check out the slideshow below for Walton's tips to launch your own reinvention.

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  • Find What Fascinates You

    Examine your life up to this point: What fascinates you? What, even if I don't fully understand it, really lights me up? What is worth doing? What's most rewarding and where can I make a contributions? Dr. Shep Nuland, a retired surgeon-turned-author who was interviewed by Mark Walton, author of the book <em><a href="" target="_hplink">Boundless Potential</a></em>, suggests, "...look back, begin to rediscover who you were when you were 15, 25, or 30 with all that wide range of things that fascinated you that you gave up to become a doctor, lawyer, engineer, business executive and so forth, to care for a family or whatever."

  • Look For "Flow"

    Explore ways in which your personal fascination can be translated into action -- into real-world work you would deeply enjoy, and that would empower you to succeed, Walton writes. Track all the different activities you do, both at work and outside of work, and write down whenever you find yourself experiencing "flow," Walton advises. This concept, created by psychologist Mihaly Csikszentmihalyi, is characterized by a sense of being so engaged in the activity that time disappears; a sense of clarity, energy, creativity and joyful mastery. What aspects of your work or leisure activities evoke a sense of flow?

  • Don't Be A Business Card

    "After being a 'grownup' for 20 to 30 years, there is a certain 'tranquilized obviousness' to our lives, to who we 'hold ourselves' to be," writes Mark Walton, author of <em>Boundless Potential</em>. "We have become, in many ways, what we print on our business cards... Psychologists call this 'institutional identity.' It took us a long time to develop these roles for ourselves, and if we have been successful, they have served us quite well. ...Recognizing our fascination necessitates looking behind the labels we have adopted, penetrating our own PR." <em>Flickr photo via: <a href="" target="_hplink">Needoptic</a></em>

  • Pay It Forward

    As you weigh your reinvention strategy, consider work that leaves a legacy. Psychologist Erik Erikson said "In adulthood you learn to know what and whom you can take care of." As author Mark Walton writes in the book <em>Boundless Potential</em>: "...Erikson held firmly to the conviction that by creating a legacy through our love and work, by paying it forward, we generate, for ourselves, a higher order of existence -- a level of well-being and self-fulfillment that is otherwise rarely experienced." <em>Flickr photo via: <a href="" target="_hplink">TinyTall</a></em>

  • Think Like An Entrepreneur

    Whether your reinvention involves a project, a role, a career, a business or a nonprofit, think like an entrepreneur, advises Mark Walton, author of <em>Boundless Potential</em>. Consider marketplace structures and unserved niches of demand that will allow you to pursue your new work. On the financial side, pay off any revolving debt, such as credit cards, and figure out exactly what you are spending each month. Then, set aside at least six months' of living expenses to help fund your transition. Don't buy into the illusion of safety of a full-time job, Walton adds, noting that the unemployment rate for post-midlife workers doubled from 2007 to 2009, to the highest level in at least 60 years.