In a recent e-mail essay, Gary North asks one of the most important questions of my generation: How does an older person get time back on his side? The answer, Gary says, is to give up the will-o’-the-wisp known as the retirement syndrome. You can keep working if you have to. And unless you have banked at least half a million bucks (and possibly much more), you have to. The good news is this: Working can be fun. In fact, if you do the right kind of work, it can bring you a great deal of pleasure. The trick is to do something you value and value what you do.

Gary provides several examples of people who have taken on challenging but valuable work in their senior years:

* Irving Brant, a journalist and playwright, decided at age 57 to write a book on James Madison. That project took 20 years, 1941-61, and resulted in a six-volume set that remains the definitive Madison biography. After that project was over, Brant wrote “The Bill of Rights,” which won the National Book Award in 1966. He was 81 years old when he won it. He died in 1976 at 91.

* Dumas Malone won the Pulitzer Prize at age 83 for five of his six volumes on the life of Thomas Jefferson. He, like Brant, had begun his project at age 57. He completed volume 6 at the age of 89. He died at age 94.

* Winston Churchill became prime minister at age 67. That was the first time. He was 78 when he became prime minister the second time, in 1951. He also wrote some of the most eloquent historical books in the English language.

* Ludwig von Mises, an economist who wrote his first major book at age 31, fled Austria before Hitler invaded, came to the United States penniless in 1941, started over, taught at New York University, proceeded to write several major books, and published his last article in 1966 at the age of 85. One of his former seminar students, Friedrich Hayek, won the Nobel Prize in 1974, based mainly on ideas he had refined from Mises’ work.

* Then there’s Jack LaLanne. “I don’t like to think about Jack LaLanne,” Gary says. To understand why Gary feels that way, take a peek at a photo of Jack, taken when he was 83, on the following website: http://www.usatoday.com/life/health/doctor/lhdoc162.htm “Don’t tell me he dyes his hair,” Gary adds. “It won’t help.” In past messages, I’ve talked about other seniors who achieved great things late in life.

And I told you a little bit about my dad, who at age 79 took skiing lessons, at age 80 had a role in a movie, and at age 81 (his current age) got through a quintuple (don’t even talk to him about quadruples) bypass followed by pneumonia and then the flu — and was doing bicep curls and knocking down Dewers six weeks later. You can keep going. The trick is to find work you enjoy. If you can do that, the rest is easy.