Generation X — as the 46 million stereotypically sarcastic, self-doubting slackers born between 1960 to 1965 and 1977 to 1982, depending on who's doing the defining, are known — is no longer the media darling, as baby boomers blossom into senior citizens and coddled 20-somethings hog the rest of the spotlight. But its emphasis on open-sourcing, independence and irony has quietly transformed lives, and now "Xer" writer Jeff Gordinier is calling on his cohorts to step up their effort.

His first book, "X Saves the World: How Generation X Got the Shaft But Can Still Keep Everything From Sucking" (Viking) is a nostalgic, hot-and-bothered survey of what Gordinier calls the "Gen-X odyssey" from coffeehouse cynics to dot-com millionaires and social innovators. Xers are, bit by bit, "changing the world," he claims, even as that 1960s phrase makes most of them sick with suspicion.

Born in the "leviathan shadow of the boomers," whose "incredible shrinking values" Gordinier skewers, Xers honed a sharp sense of skepticism and separateness, "afraid to commit to their lives because they see so much of the world as a cliche," he writes. He cites Beck, one of the generation's hit singers.

Wary of canned idealism and false hopes but still drawn to the desire for change, Xers launched their own micro-revolutions instead, creating companies such as Netscape, Google and Amazon that empowered individuals and triggered a ripple effect that gave even small ideas huge potential.

Xers held the helm of pop culture for a short time — an era book-ended by opposing gym scenes in music videos for Nirvana's anarchic "Smells Like Teen Spirit" and Britney Spears' regimented "Hit Me, Baby, One More Time."

Those Xer 1990s saw a new generation's intensity, innovation and "social promise" upend old orders in art, advertising and business, as the dot-com boom turned their "loafer's love of freedom" and "lizard-eyed respect for commerce" into hot market traits, Gordinier says.

"About money it was chic to be clueless. Then all of a sudden it was not," he writes.

Yet when the bubble burst and stocks crashed in 2000, Xers found relief, not demise. Their generation had always preferred to do its own thing, undisturbed, like bugs under a log, Gordinier says.

Rather than fight, then, for keys to the kingdom — which slow-to-retire boomers are unlikely to hand over — Xers have continued creating their own "rogue colonies," with companies such as YouTube, Wikipedia and Meetup nurturing an infinite number of niches and channels of communication that are antidote to the "American Idol monotony of mass culture," Gordinier says.

A one-time rock and film critic who is now editor-at-large at Details magazine, Gordinier uses wild analogies and anecdotes to catalog Xer music, movies and business models, and to deride the self-involvement and vapid "me-me-me" chorus of the 70 million baby boomers who precede X and the 70 million "Generation Yers" who follow.

Gordinier paints his reflections in pop color, comparing Kurt Cobain to John Donne and deconstructing "Willy Wonka and the Chocolate Factory" as his generation's primary moral parable. But he also emerges with a new, grown-up-Xer call to action.

"When it comes to changing the world the boomers choked" on their own self-importance, he writes. "We have a chance now, as yuppies, or just as adults, to cull whatever capital, influence, and media savvy we've amassed and to use it for good."

"X Saves the World" is not just a kitschy title but a serious proposal. And for skeptical Xers, the ability to embrace a new, measured hope may be the mark of maturing.

That coming of age is embodied by the first Xer presidential contender, Barack Obama, Gordinier suggests. Born in 1961, Obama's own journey from irony to idealism is breathing new life into the phrase "change the world."

That is exactly what Gordinier is asking Xers to do: to stop brooding, take stock of their accomplishments and think big.

For members of the generation he is prodding, Gordinier's book is a sometimes uncomfortable reminder of how crippling and tiresome all that cynicism and self-doubt really were.

But instead of wincing at the past, he is giving us a chance at redemption, urging us to stop resisting and to embrace the impulse we've always wanted to: to stand up and do good.