For most right-thinking music fans, crossbreeding rock with classical music is the worst kind of genetic engineering. Too many rock stars with Costco-large egos and highbrow delusions of grandeur have attempted to stretch creatively by composing large-scale symphonic work—a notion born of the same hubristic impulse that leads second-rate soap opera stars into thinking they could really nail Ibsen if given half a chance.

Just pick your way through the trash bin and behold the gauzy pretension of Billy Joel's fake Chopin piano concertos (as performed by Richard Joo) on his appropriately titled CD Fantasies and Delusions (2001), which mimics classical tropes with little imagination: Paul McCartney's Liverpool Oratorio (1991), an overblown melodrama in which McCartney's sentimental instincts turn orchestral music into soap-operatic gruel; and Pink Floyd alumnus Roger Water's Ça Ira (2005), a musical that makes Andrew Lloyd Webber's work sound nuanced and understated.

It's unclear whether these otherwise gifted composers "went classical" out of some artistic yearning or simply because they felt the need to show off by mastering the most complex of musical forms. One thing's for certain: no matter how hard they may have tried, the end result still sounds like something a rock and roller would come up with. The pseudoclassical pieces tend to have clamorous, amplified music thrown into all the wrong places and count on a string section to glass over any deficiencies.

As a child of progressive rock, though, I've always been drawn to the idea of lashing rock and classical music together. Ever since I heard Procol Harum's album Live in Concert with the Edmonton Symphony Orchestra in the early '70s, as well as Emerson, Lake and Palmer's Wagnerian experiments with classical music, I've held out hope that some rocker somewhere, would not simply embellish rock compisotions with string arrangements (a staple of prog rock), but would write something seamless.

Is it any wonder that it was Elvis Costello, rock's most protean songwriter, who finally figured it out? His large-scale orchestral composition, Il Sogno (The Dream), which the San Francisco Symphony performs this month, is an ambitious and fully realized classical work, a generous, subtle, and spirited opus. Listen to the 2004 recording of Il Sogno as interpreted by Michael Tilson Thomas and the London Symphony Orchestra, and it's quickly apparent that Costello isn't another slumming rock star.

But then, few rock artists have shown Costello's artistic intelligence, his capacity to absorb musical idioms and then create something new. Even early in his career, it seemed rock just couldn't contain him or completely satisfy him. His first album, 1977's My Aim Is True, audaciously roamed across the musical map; Costello's songs moved from the jittery, raggae-tinged "Watching the Detectives" to the tender ballad "Allison" as if such versatility were the most natural thing in the world. His subsequent, three albums flashed gleaming pop, Motown soul, and snarling, cynical punk

So deft is Costello at shape shifting that he quickly sheds whatever labels critics bestow on him. Early on, while he was being embraced by first-generation punk rockers as their Dylan, he released Almost Blue, which covered songs by country singers George Jones and Merle Haggard, among others—not necessarily a cool thing to do in 1981. Five years later, Costello offered up King of America, which drew from American roots music. In 1998, he collaborated with composer Burt Bacharach ("Walk on By," "The Look of Love") on Painted from Memory, an album that expertly echoed Bacharach's great baroque pop of the '60s. His recent album The Delivery Man was recorded in Oxford, Mississippi, and featured guest singers including Lucinda Williams and Emmylou Harris.

So it's no surprise that Costello has had a long interest in classical music, going back to 1993's The Juliet Letters, an experiment in art song with Britain's Brodsky Quartet. More recently, he's written chamber music for Britain's Composer's Ensemble and Academy of St. Martin in the Fields, as well as lieder for Swedish mezzo-soprano Anne Sophie von Otter. There's always been a touch of the aesthete in Costello—even at his most ferocious, he's never sacrificed craftsmanship for attitude.

In 2000 the Italian dance company Aterballetto commissioned Costello to write the music for its full-length ballet adaptation of A Midsummer Night's Dream. According to the liner notes on the London Symphony Orchestra recording, Costello approached the task the old-fashioned way, writing his own musical notation with a pencil. That's important, because it means that Costello set his ideas straight onto paper without intervening transcribers or arrangers.

As befits Shakespeare's magical fable, Il Sogno has a dreamy quality, a woozy lushness that evokes sprites dancing in some verdant dreamscape of the imagination. It is unabashedly romantic and gorgeous; no squonky dissonance or 12-tone exercises here. The lush strings and billowing horns seem to inhale and exhale like a Victorian-era bellows, emitting a gentle sound broken by interludes that bring to mind Stravinsky's music from Petrushka. As with that ballet, you can imagine both children and parents enjoying Il Sogno.

Predictably, Costello's palette is large. One can discern elements of romantic composers like Sibelius during the lovers' sections, the dark tonal colors of Mahler when things get dramatic, Gershwin's sensual, swaggering jazz in moments of joyous uplift. Costello has paid close attention to dramatic structure; his piece reflects the push and pull of the story. It's the same vivid story-telling we've come to expect from him. He's just using a large orchestra instead of lyrics to do it.

And Costello weaves in his rock music elements with care. In act 2, when Oberon and

On Il Sogno, Costello pulls off the classical move with grace and aplomb, but let's hope it doesn't lead to a rash of similar experiments from other rock stars. If Elvis Costello has proven anything in his long and prolific career, it's that he is truly sui generis. He just might be the only rock and roller who could write something like this. That baton cna't be handed off to just anyone.