One of rock ‘n’ roll’s greatest and most overlooked assets is its flexibility. Conservative genres like blues and country change over time but only in incremental doses. If there are revolutions in those art forms, they tend to occur in bloodless, piecemeal coups. A country or blues artist from 50 years ago would have little difficulty recognizing and appreciating the best music of those genres today.

But like jazz and classical music, rock ‘n’ roll has shown a capacity to accommodate radical alteration. No matter how violently the form is manipulated, it usually maintains its essential “rock” quiddity. That’s why the Moody Blues, the Residents, the Velvet Underground, Rush, the Beatles, and Jonathan Richman are all members of the rock family. Elvis would probably have trouble acknowledging Pere Ubu as a cousin, but that’s how quickly and drastically rock music can change. That knack for shape-shifting has rankled those who would like to keep rock’s gene pool pure, but it’s also what’s kept it so interesting.

The freedom to redefine themselves once a particular niche becomes confining or boring has been a godsend for a number of rock’s more creative artists. Neil Young is still vital long after his Woodstock cohorts have become flabby inanities. That’s because he’s been able to artistically reincarnate himself from a Buffalo Springfield pop star to a laid-back folkie to a feedback-wielding firebrand. Likewise Captain Beefheart has evolved from straight R & B howler to psychedelic dadaist to exceptional avant-garde composer.

Brisbane, Australia, native Ed Kuepper has had a similarly lengthy and artistically fruitful career, though one less well documented. Like Beefheart and Young, Kuepper has reinvented and reinvigorated himself over and over for nearly 20 years. Kuepper was one of the original punk rockers of the late 70s. With Chris Bailey he started the Saints, the legendary Australian band whose punk classic “(I’m) Stranded” actually predates the Sex Pistols’ first vinyl salvo. The Saints equaled their British counterparts in surly discontent and rushing guitar charge, yet Kuepper’s songwriting gave them a bit more musical heft. The Saints’ third record, Prehistoric Sounds (1978), saw Bailey and Kuepper abruptly drop punk for a slow, brooding R & B sound. The anger and resentment were unabated, but there were no more blunt three-chord attacks. Shortly after the release of Prehistoric Sounds, Kuepper left the band.

The following year he formed the Laughing Clowns, whose odd amalgam of rock and free jazz featured upright bass, drums, trumpet and/or tenor sax, occasional piano, and Kuepper’s abrasive guitar scraping. The prickly songs, among Kuepper’s blackest and most disillusioned, paid mere lip service to their key signatures and sometimes included free-blowing tenor and trumpet parts. It was as if Ornette Coleman’s classic early-60s quartet was dabbling in rock ‘n’ roll, though the Clowns clearly weren’t in Coleman’s league. Later records were more rock oriented, but the improvised dissonance and odd song structures remained.

In 1984 Kuepper set to work recording his first solo record, Electrical Storm. This time he pared things back to bass, drums, and lots of acoustic guitar to deliver a collection of straightforward, restless songs of rough-hewn lyricism. Electrical Storm revealed a striking melodic ability that had been gestating throughout his earlier work. Yet Kuepper’s melodies were never ornate; they had a rustic charm that owed more to folk than to the Beatles.

Over the past ten years Kuepper has recorded a series of records alternating between dense, well-produced guitar pop (Everybody’s Got To, Black Ticket Day) and more personal and haunting acoustic efforts (Today Wonder, Serene Machine). In 1991 Kuepper assembled a new band he christened the Aints, who’ve released two records of overamplified, distortion-fractured songs in the MC5/Stooges tradition that revisit and elaborate on Kuepper’s punk rock roots.

Restless Records recently agreed to distribute some of Kuepper’s back catalog in the U.S. The first installment is The Butterfly Net, a compilation from Kuepper’s solo records of the last ten years that also includes rerecordings of some Laughing Clowns and Saints tunes. Although it leans heavily to the pop side of the Kuepper canon, the album does provide a glimpse of his multidimensional muse. The dour balladeer and the unrepentant rocker appear with only slightly less frequency than the slick craftsman.

The Butterfly Net contains some vintage Kuepper nuggets: the despairing “Electrical Storm,” the propulsive and sarcastic “Also Sprach the King of Euro-Disco,” and the inoculation-proof infectiousness of “The Way I Made You Feel.” But like most compilations, it’s designed to whet rather than satisfy the appetite, and ultimately ought to send you beating the bushes for his excellent older records. A final note: this month Restless is also releasing Kuepper’s new studio album, Character Assassination, a fine collection of sometimes breathtaking acoustic tunes that won’t hurt the Kuepper legacy one bit.