By Tom Johnson

I have just turned 40-an unavoidable result of my birth year, 1971.?This places me in the belly of that great population plunge known as Generation X.  Our elders were born around 1965 (Charlie Sheen), our youngest around 1978 (Ashton Kutcher).   We were the ones reared on T.V., divorce, the Cold War, and the first home computers.  But now at 40, Gen X can seem like a bust.

My generation exists in the shadow of the thunderous Baby Boom, almost doubling our size.  That is probably why the Boomers always seem so captivating-the age-defying renegades who transform America. This year, as they begin to turn 65, they're at it again, reinventing yet another stage of life.

On the other hand, we seemed to peak with the dot-com bubble in the 1990s before shrinking into obscurity after the world remembered CEOs probably shouldn't be 23 and venture capital eventually runs out.  Maybe we bought into our slacker label, as America shoved us into the attic like a box of old CDs the moment a newer, more digitalgeneration came of age.

Quietly turning 40 with me this year is Tea Partier Marco Rubio-maybe this Latino-vote-courting star will pave our political future.  There's actor and TV producer Mark Wahlberg, coming a long way from his days as Marky Mark in Calvin Klein's. Also turning 40 are the creators of Borat, South Park, and even the first electric car.  We're accomplishing stuff, yet America couldn't care less.

So what will be our legacy?  Searching for the answer, I discovered another group that has been overlooked.

The Silent Generation was born during the Great Depression, and has lived ever since in the shadow of the celebrated WWII-fighting GIs.  Think of those black and white films with the returning war hero mobbed by family and friends, beautiful girlfriend dipped back for a kiss.  Now picture his quiet little brother looking on (it wasn't a speaking part).

They got their moniker from a cutting 1951 Time magazine profile that explains,  "The most startling fact about the younger generation is its silence… Youth today are not cynical, because they never hoped for much."  One Silent member believed his generation "suffers from lack of worlds to conquer. Its fathers, in a sense, did too well." This is the generation that would never produce a U.S. President.  Even the war in which they served, Korea, is called the "Forgotten War".

But historians William Strauss and Neil Howe note that the Silents are named for how they began their journey, not where they ended up.  While America dismissed them, they were busy changing America: ushering in Civil rights, women in the workforce, and rock and roll.

As it turns out, the Silents are enjoying something of a Renaissance these days.  TV's "Mad Men" is the story of "Dick Whitman," born during the Depression and raised on a hardscrabble farm, reinventing himself as Don Draper, Madison Avenue superstar.

So here we are, Generation X in the shadow of the Baby Boomers, the Silents in the shadow of the Greatest Generation.  From a Silent Gloria Steinem to a Gen X Tina Fey.  From a Silent John Lennon to the Gen X Google guys.  From a Silent Daniel Ellsberg to a Gen X Julian Assange.

Like the Silents, maybe Generation Xers are the ones no one saw coming.  Maybe that's our legacy-we will change America while flying under her radar.

And by the way, Don Draper is played by the actor Jon Hamm-and he turned 40 this year, too.