Trying to absorb Charles Mingus's "Epitaph" during its premiere performances at Lincoln Center and Wolf Trap last summer was a daunting task -- the "jazz symphony" involved 30 musicians playing 19 different movements and 130 minutes of ambitious, ever-shifting music. The task is only somewhat easier now that Columbia Records has released the Lincoln Center performance as a double-CD set. As one plays and replays it, one gradually catches the musical quotations, the structural shifts, the internal byplay and repeating motifs that make "Epitaph" a landmark composition.

As the title implies, Mingus intended this "symphony" to be his musical obituary, a summing up of all his musical and emotional dimensions. Mingus was a bulky, imposing man physically, and his passions and appetites were even larger. To encompass them all required a composition of unprecedented size and shape. A symphony possesses no more inherent value than a pop song (any more than a novel is inherently more valuable than a poem), but it does have the weight and complexity necessary to accommodate a life as broad and complex as Mingus's.

His background (African American) and his personality (volatile) demanded a symphony filled with jazz improvisation. Unfortunately, there was no precedent for a jazz symphony. The major contribution of 20th-century American music has been jazz's redefinition of the relationship between composed and improvised music (for example, between European and African music or between aristocratic and peasant music). That redefinition has occurred mostly within the format of the 12-bar blues and the 32-bar song; before Mingus, only Duke Ellington successfully integrated improvisation into longer European concert forms (as in his 1943 "Black, Brown and Beige," a 50-minute suite).

Like Ellington, Mingus knew that jazz was rarely pure improvisation, that it almost always involved creating setups and structured frames for the spontaneous solos. The challenge in composing a jazz symphony was to concoct framing devices that sustained the music's growth and momentum at symphonic dimensions. Mingus scrawled more than 4,000 measures on more than 500 manuscript pages for his 1962 "Town Hall Concert." When business and personal problems turned that concert into a legendary disaster, the "Epitaph" score was shelved until musicologist Andrew Homzy discovered it among Mingus's papers in 1985 -- six years after the composer's death.

After a Herculean reconstruction job on the sprawling, disorganized score, jazz historian and composer Gunther Schuller conducted an all-star 30-piece jazz orchestra in last year's premieres. The result was not a true jazz symphony, for the 19 movements are discrete pieces with little connection other than proximity and instrumentation. In fact, many of the movements were recorded by Mingus as self-sufficient short pieces. Nonetheless, the juxtaposition of the pieces, the continuity of the instrumentation and Mingus's brooding, hovering spirit give "Epitaph" an undeniable unity.

As in Ellington's best orchestral writing (and "Epitaph" is that good), Mingus plays the expanded band like an instrument, setting sustained brass harmonies beneath a sax cadenza, for example, quieting everything for a vibraphone solo or pitting screaming trumpets against rumbling timpani. The notated music in "Epitaph" provides the soloists with good jumping-off points, and they are directed always to carry the symphony farther down the road to a rendezvous point where the orchestra can jump back on board. Mingus's music differs from Ellington's in its fondness for blues and gospel flavors and the earthy emotions they connote. Mingus, himself a double bass player, bolstered the bottom by giving prominent, tugging lines on nearly every piece to the two bassists, three percussionists, two baritone saxophonists, tuba player and contrabass clarinetist.

He rearranged several old tunes (Vernon Duke's "I Can't Get Started," Thelonious Monk's "Well, You Needn't," Jelly Roll Morton's "Wolverine Blues" and his own "Pithecanthropus Erectus") so radically for his epic orchestra -- often introducing new melodic figures -- that they nearly become new compositions. Mingus has always been underrated as a lyric composer, but the romantic ballads within "Epitaph" -- "The Soul" and "Noon Night" -- are just waiting to become standards. On the other hand, the symphony's more abstract, academic movements, such as "Moods in Mambo" and "The Children's Hour of Dream," are among his least satisfying compositions.

The CD comes with a 44-page booklet with detailed notes by Homzy and Schuller. It's worth fighting through Schuller's dense, forbidding prose to appreciate his dissection of each movement. His conducting has a similar cerebral emphasis: The musicians' intonation and phrasing have a classical precision but lack the lustiness and humor of Mingus's own bands. A comparison of Columbia Records' version of the Lincoln Center show and National Public Radio's national broadcast of the follow-up Wolf Trap show indicates that the musicians were a wee bit less tentative and more expressive in Virginia. It's no contradiction to say that Schuller's "Epitaph" is a treasure but also to hope that it's not the last version we get to hear.

Miles Davis: 'Aura' Another jazz symphony appeared late last year when Columbia Records finally released the 1985 recording of "Aura," a 60-minute piece composed by Denmark's Palle Mikkelborg in honor of Miles Davis winning the 1984 Sonning Music Prize in Copenhagen (past winners include Stravinsky, Messiaen, Copland and Bernstein). Davis himself and his longtime sidekick, guitarist John McLaughlin, are the featured soloists, and they are joined by two percussionists from Davis's band, bassist Niels Henning Oersted Pedersen and the 26-member Danish State Radio Big Band.

Mikkelborg used Schoenberg's serial method of composition to get started: He assigned notes to the 10 letters in M-I-L-E-S-D-A-V-I-S, and altered that sequence of notes for each of the symphony's 10 movements, each corresponding to a color in Davis's "aura." Fortunately, Mikkelborg used this gimmick very loosely and concentrated instead on his impressions of Davis's musical career (with a special emphasis on his collaborations with orchestral arranger Gil Evans). The results do just what a "jazz symphony" should do: They create the most sympathetic settings possible for the soloists.

Few American musicians would mesh well with Mikkelborg's Scandinavian restraint -- there's a moody minimalism and a chilly reserve that take some getting used to -- but those qualities play to Davis's strengths, and he responds with that distilled, vulnerable trumpet sound no one else can duplicate. His acoustic period is recalled on "Blue" (with a two-note riff as in "So What"), "Green" (a tribute to Evans) and "Indigo" (a Bill Evans-like piano piece that doesn't feature Davis at all). Most of the other pieces evoke his electric period, but with the clutter removed. The rhythm section percolates provocatively, but the focus is on Davis and McLaughlin, whose piercing, economical solos fulfill the long-delayed promise of their collaborations at the birth of fusion.