When two enfants terribles like Pierre Boulez and Frank Zappa join forces, one expects either imminent disaster or immediate chemistry. Fortunately, the latter prevails in "Boulez Conducts Zappa: The Perfect Stranger" (Angel DS-38170.)

At first glance, this album title seems perfectly appropriate. What possible similarities could Boulez, the brilliant avant-garde composer and conductor, share with Zappa, the satiric rock star who has been composing "seriously" half his life? Plenty.

For starters, both men invite, in fact revel in, controversy. As music director of the New York Philharmonic in the '70s, Boulez invoked howls from subscribers expecting heavy doses of Brahms and Tchaikovsky, not the Schoenberg, Berg and Webern he regularly programmed. If that weren't enough, Boulez, through his numerous writings on musical and socio-musical topics, even managed to alienate his supporters.

Zappa has been no less shocking. With his group, the Mothers of Invention, he took rock to the lunatic fringe. Using a "parity of parody" philosophy, Zappa lampooned pop music and exposed his mordant wit prominently in such classical "tributes" to Stravinsky and Debussy as "Igor's Boogie" and "Prelude to the Afternoon of a Sexually Aroused Gas Mask." "Dada Was Here" might best describe a typical Zappa performance, on disc and especially live.

Boulez and Zappa, however, are alike in ways more important than their ability to infuriate. On "The Perfect Stranger," they meet on common musical ground, which may be summed up in two words: Egard Varese. This French composer's music influenced the early works of Boulez and convinced a young Francis Zappa that composing would be his chosen career. The formally trained Boulez and the self-taught Zappa have never lost sight of Varese's sound-for-sound's-sake principles, the sort typified by his Ionisation, for 13 percussion instruments, and Integrales, for chamber ensemble.

Nowhere is this more evident than in "The Perfect Stranger," which Boulez commissioned Zappa to write. The work, the first of seven dance pieces with plots and, as Zappa explains, "built-in sound-effects," proceeds from a corny chiming doorbell through a series of musical tableaux that scarely suggest the story line -- a potential vacuum cleaner sale to a housewife as viewed by the pet dog. Boulez and the 29-member Ensemble InterContemporain give a stunning account of the score, rich with Varese-like percussion patterns and colorful themes in the woodwinds, reminiscent of Stravinsky.

In "Dupree's Paradise," Zappa unveils a work exploiting different instrumental colors. Strangely enough, he evokes Gershwin in his effort to re-create a bar scene in the Watts section of Los Angeles at 6 a.m. where musicians, winos and cops interact unpredictably. This "An American in L.A." has a cinematic feel, thanks to the sparkling orchestration carefully attended to by Boulez.

The conductor and the Ensemble InterContemporain appear on only three selections; the remaining chamber works feature the Barking Pumpkin Digital Gratification Consort. One can surmise that Zappa is among the uncredited participants, if not the entire group. The Consort blends what sounds like electronically altered marimba, vibraphone, xylophone and celesta textures in "The Girl in the Magnesium Dress." The musical quickie "Love Story," an attempted sexual liaison between an elderly couple break-dancing, is rife with percussive pings, suggesting popping corset stays.

Less humorous and altogether more choreographable (these are, after all, dance pieces) are "Jonestown," a harrowing array of metallic, clanging noises and sirens, and "Outside Now, Again," a Zappa nod to minimalism. "Outside," buoyed by an ostinato in 11/4 and a moderate tempo, is a hand-delivered invitation to dancers.

"The Perfect Stranger" is a near-perfect merger of sympathetic conductor and composer talents. Angel's digital mastering and ultra-clean sufaces bring out a depth and clarity to the music. Zappa disclaims his compositions as being "for entertainment purposes only, and should not be confused with any other form of artistic expression." This is the same mock-sarcastic voice that once proclaimed classical music to be the "province of old ladies . . ." Zappa, just as he likes to stretch the ears of his rock fans, likes to tweak those of the classical music public he welcomes with semi-open arms and well-sharpened barbs.