Frank Zappa, who died last week at age 52, received commissions from the Kronos Quartet and Pierre Boulez, was acclaimed as a genius by conductor Kent Nagano and was nominated by President Vaclav Havel as Czechoslovakia's cultural ambassador. On the other hand, he has been twice rejected for admission into the Rock and Roll Hall of Fame, and his music was dismissed in Robert Christgau's Record Guide to Rock Albums of the '70s as "sexist adolescent drivel ... with meters and voicings and key changes that are as hard to play as they are easy to forget."

Admirers and detractors agree that Zappa's music -- with its odd time signatures, unorthodox harmonies and fiendishly difficult lines -- boasts a rare cerebral complexity. But that's where the agreement ends. Some fans find his sophomoric jokes ("Don't Eat the Yellow Snow") and pop music parodies ("Sheik Yerbouti") a crucial counterbalance to the rarefied density of the music; other devotees find the jokes an irrelevant sideshow to music best appreciated in a chamber or orchestral setting. The critics find the humor's smug iconoclasm a symptom of the essential emptiness of Zappa's intellectual exercises.

The controversy over Zappa's true place in American musical history is bound to rage for years to come. He released more than 75 albums during his lifetime, and more are sure to follow as his voluminous tape archives are mined. And Zappa, who always claimed he was more a composer than a performer, has left behind dozens of pieces that will receive additional interpretations in the future. The Baltimore Symphony Orchestra, for example, performs Zappa's "Perfect Stranger" at Baltimore's Meyerhoff Symphony Hall on Thursday, and two albums of Zappa music performed by other ensembles have just been released.

'The Yellow Shark' Zappa, who fell in love with Edgard Varese at age 13, was composing classical music before he ever turned his attention to rock-and-roll. He always complained, however, that performances of his classical music were plagued by inadequate rehearsal and institutional politics. The only two performances he ever endorsed were Pierre Boulez's 1984 version of "The Perfect Stranger" (reissued last year on Barking Pumpkin Records) and the Ensemble Modern's 1992 performance of "The Yellow Shark" (released this fall on Rhino Records).

"The Yellow Shark" makes the best possible case for Zappa as a serious composer. The 18 members of Germany's Ensemble Modern (and its eight guests) are superbly trained classical musicians with plenty of experience in contemporary art music, and they bring a precision of intonation and a warmth of timbre that Zappa's music has rarely enjoyed. Only two of the 18 pieces feature vocals, so there are few distractions from the music. Zappa himself conducted three of them; the Ensemble Modern's Peter Rundel handled the rest, and he coaxed a surprising clarity out of this dense and tangled music.

Some of the pieces ("Dog Breath," "Uncle Meat," "Be-Bop Tango" and so on) will be familiar to Zappa's pop fans; others come from his under-exploited classical catalogue. All the music has the irreverent playfulness and technical challenges that mark Zappa's writing, but several numbers evince a soulfulness that critics have so often found lacking. Two pieces in particular, the back-to-back environmental laments "Outrage at Valdez" and "Times Beach II," evoke a heartbreaking sadness with their slow, thick harmonies that seem to absorb every hopeful brass or woodwind statement into their smothering mass. (To hear a free Sound Bite from this album, call 202-334-9000 and press 8141.)

'Zappa's Universe' A very different re-creation is "Zappa's Universe: A Celebration of 25 Years of Frank Zappa's Music" (Verve), a recording from the Nov. 7-10, 1991, performances at the Ritz Theatre in Manhattan. Fourteen Zappa songs are performed by an aggregation that includes a rock sextet, two a cappella doo-wop quartets (the Persuasions and Rockapella), the 25-member Orchestra of Our Time conducted by Joel Thome, and such Zappa-alumni guest stars as Steve Vai, Dale Bozzio and Dweezil Zappa. Ten of the tunes are dominated by broadly delivered vocals, and the amplified instruments overwhelm the orchestral ones.

In other words, this is a celebration of Zappa's worst excesses. Zappa's lyrics are usually showoff facile at best and sexist at worst (this album's "Brown Shoes Don't Make It" contains a particularly ugly rape scene), and matters aren't helped by guitarist Mike Keneally's dull, often flat vocals. The playing tends to emphasize tricky lines played at super-fast tempos, but the results sound like '80s fusion-jazz, all technical flash and no feeling. In fact, this album too often sounds like "Weird" Al Yankovic singing with the Chick Corea Elektric Band. (To hear a free Sound Bite from this album, call 202-334-9000 and press 8142.)

Reissues Frank Zappa was one of the most prolific recording artists to emerge in the rock-and-roll era. The February 1993 DISCoveries lists more than 70 Zappa CDs, and most of those are still in print. Additionally, Zappa's Honker Home Video released a half-dozen concert films, as well as the odd "200 Motels." Zappa was a compulsive anthologist who often used what he called "conceptual continuity" to link musical and thematic ideas throughout his recordings. And as far back as the Mothers of Invention's 1966 double-disc debut, "Freak Out!," he also loved putting out multi-disc sets (24 on vinyl). In the early '70s he planned a Mothers of Invention Record Club (to be distributed through Playboy) and a 12-record "History and Collected Improvisations of the Mothers of Invention," though they had only recorded six albums at the time.

Beginning in 1986, Zappa himself supervised Rykodisc's extensive CD reissue of much of the Mothers of Invention catalogue, as well as '70s albums that appeared under his own name. There have also been six double-album concert anthologies, titled "You Can't Do That on Stage Anymore," and new albums like "Broadway the Hard Way" and "Frank Zappa Meets the Mothers of Prevention." A number of albums, mostly recorded in the '80s, were released on Zappa's own mail-order Barking Pumpkin and Foo-ee labels, and Foo-ee released (through Rhino) two boxed sets of Zappa-authorized bootleg recordings ("Beat the Boots").