The clock is ticking on classic rock: that great age of forty or more years ago, when the musicianship and lyricism of the post-Woodstock years just sorta peaked, and the whole world just bought a Coke, harmonized, perfectly, and went to the dark side of the moon. Rock'n'roll decided to go to college and, during the decade-long romance of the 1970s, out came this intergalactic baby prodigy called progressive rock.

With Brit bands consisting of art-school dropouts and classically trained musicians, acts such as King Crimson, the Moody Blues and Gentle Giant set the pace to the mellotron sky, reclaiming the tradition of the great English poets going back to William Shakespeare, giving us at least two things. The first, painted sound creating visual landscapes in your head reminscent of classical music set to nursery rhyming metaphors or set in avant-garde netherworlds. Some critics, scorning it all, called it "flash rock." The second thing to come out of it all was punk rock, emerging from the pure frustration that most performers couldn't reach those heights.

Nope, you had to be a genius of some kind to play that kind of music, and intellectual acuity will only get you so far with the rest of your stoner friends in the mundane world. But now, think about this: Soon, many of the artists of the short-lived age of progressive rock will be passing on, unable to perform at even the casino as a has-been name-brand band. I mean, have you seen Peter Gabriel's waistline lately, and, hey, Roger Daltrey! Put on a shirt!

Even the classic rock tribute bands are aging. Consider Living With the Past, the planet's only "officially sanctioned" Jethro Tull tribute band.

"We are the only endorsed Jethro Tull tribute band in the world," says Ray Roehner, group leader for Living With the Past, who has been interpreting the "Baker Street muse," the Pied Piper of prog rock, for two decades. "A lot of tribute bands are kind of corny," he says. "I like the act that tries to do the music, and not focus so much on the way bands dress and the antics. People appreciate the sincerity of doing that without the mimicry."

Roehner, who says he's an associate of Tull's Ian Anderson -- the bug-eyed, flute-whipping, Pan-like whirling dervish who launched the iconoclastic "underground" group in the late 1960s -- doesn't attempt any of the on-stage mannerisms, such as standing on one leg while he plays. Indeed, trying to play such tricky music is hard enough. "If you let your mind wander a bit, you are lost," Roehner says. Yep, you'd better keep up on the coffee to focus on the ornate, exacting time shifts of "Songs from the Wood," or, as Living With the Past does, the first 26 minutes of "Thick as a Brick."

Roehner, who lives in Sedona but is flying his band in from New York, along with a large cache of vintage instruments, including Pearl Jam's old drum kit to get the fills right, and a piano "that weighs a ton," has kept in contact with Anderson over the years. The actual Tull leader, now performing as Ian Anderson (including a date in Mesa this fall), has recognized Living With the Past's dedication to his music. Roehner and the creator of such 70s rock staples as "Aqualung" and "Bungle in the Jungle," have a kind of collaborative relationship. For that reason, Roehner doesn't like to steal Anderson's visual eccentricities.

"He keeps up on what we are doing and he gets ideas from us, such as how we structure a set or combining and incorporating things, and he's done that with his shows," he says. "But jumping around and throwing the flute around while standing on one leg, it's kind of like his signature, and he's been very gracious in letting us do this. People tell me you really need to stand on your leg while you play. Those are his moves and I just don't feel comfortable doing that."

From a distance, Roehner looks a bit like Anderson on stage, and he's certainly capable of capturing the Tull leader's accents on the flute. The rest of the band, with its two guitarists, makes one appreciate original Tull guitarist Martin Barre. His legacy in the annals of hard rock from the 1970s and 1980s is really captured by Living With the Past.

The opening act for the Tull tribute, Adrian Conner, a guitarist, singer and songwriter who has her own band, Adrian & the Sickness, but also does an AC/DC and Judas Priest tribute band called Hell's Belles, says she wouldn't be able to make a living as a musician without her "day job," that is, covering Angus Young and Rob Halford tunes.

"I wouldn't have been able to put out seven of my own albums without doing Hell's Belles," she says. "It's not easy to find paying gigs playing original music these days."

But Conner should get more notice for her own work. She is a tremendous player who attacks the guitar, and her stage antics are more than just entertaining. Her delivery of Jimi Hendrix's "Little Wing" had a number of people in the small crowd at a recent show at the Oprheum in Flagstaff, Arizona, drew some raves. After her relentless shows, she sold more than a few CDs ... of her own music combining classic rock riffs with a more punked out, Joan Jett & the Blackhearts orientation.

In this age of the "American Idol" karaoke star, we can all pause and wonder how tribute bands, if they are good enough to get out of the bars, like these two bands, just how they can get good enough to go out there and sound like Jerry Garcia on guitar, Keith Moon on the drums, or Ian Anderson on the flute. Takes a musician with some peculiar skills as both musician and actor to pull it off. And someday, just imagine. It won't be that classical pianist drawing grants from the National Endowment for the Arts. Instead, it will be four cats who can deliver "Stairway to Heaven" note-for-note. That'll be the day job creation for musician-actors reaches "The Great Gig in the Sky," when a Jethro Tull, Pink Floyd or Genesis performance is as common as Shakespeare in the park.