Jazz never has existed in a vacuum. Even in the '60s, when free improvisation flourished, and widened the gap between some segments of the jazz audience, ther era's principal innovators, Ornette Coleman and John Coltrane, clearly were indebted to previous generations.

Twenty years earlier the harmonic complexity of bebop may have sounded like so much Chinese music to traditional and swing-jazz fans, but bebop didn't simply burst forth full-blown from the horns of Dizzy Gillespie and Charlie Parker; it owed much to the creative achievements of Louis Armstrong, Don Byas and many others.

In recent years there's been an increased awareness of this continuity. Collaborative efforts by Max Roach and Anthony Braxton, as well as the late Mary Lou Williams and Cecil Taylor, have narrowed the generation gap, if not made the issue irrelevant. Air and Arthur Blythe have created fresh contemporary settings for works by Duke Ellington and Scott Joplin. And young saxophonists such as Scott Hamilton and Richie Cole favor tones that consistently recall masters of the swing and bop eras.

The latest example, and certainly the most natural collaboration, is a family affair called "Fathers and Sons," an album shared by two jazz families, the Marsalises of New Orleans and the Freemans of Chicago. Sadly, though perhaps not surprisingly, it's the sons rather than the fathers whose names are best known; and it's the sons who will perform at Sunday's Kool Jazz Festival at the Kennedy Center.

Through a brief association with Art Blakey's Jazz Messengers and a highly acclaimed debut album, trumpeter Wynton Marsalis has established a national reputation at age 20. His father never has basked in the limelight: The reputation of Ellis Marsalis, a pianist and educator, is largely confined to New Orleans. The third member of the clan appearing on "Fathers and Sons" is Branford, a promising saxophonist who frequently records with brother Wynton.

A similar relationship exists in the Freeman family. Von Freeman is an extremely well-known saxaphonist in the Chicago area but his national audience is overshadowed by his son's. Chico Freeman, also a saxophonist, recently has emerged as one of the most creative jazz artists in the post-Coltrane era. Even in the short time he's been recording, his available albums outnumber his father's.

What makes "Fathers and Sons" more than just a clever idea is the remarkable compatibility these musicians display. The Marsalis family, along with bassist Charles Fambrough and drummer James Black, have the first side all to themselves. In a series of brisk choruses each family member presents his credentials: In the opening number, "Twelve's It": Branford's tone is agile yet muscular; Wynton probes with his typical precision; and Ellis' contribution is no less contemporary.

If "Fathers and Sons" holds one revelation it's the extent of Ellis' stylistic reach. He wrote four of the the five pieces, the other being an especially thoughtful interpretation of Billy Strayhorn's "Lush Life." And each number seems to reflect another facet of his playing. "A Joy Forever," for example, is a loping blues in which Wynton and Branford share more than a passing resemblance to Miles Davis and Wayne Shorter. Ellis completes the picture by recalling Wynton Kelly's sympathetic touch.

Ellis is a different sort of pianist at other times. He can be emphatic and percussive, on the order of McCoy Tyner ("Nostalgic Impressions"), bring a swift yet lyrical improvisation to others ("Futuristic") and interpret a ballad like "Lush Life" with clarity and warmth.

By contemporary standards Marsalis' compositions, all less than five minutes long, are brief and rather conventional. There is, however, ample room for the brothers to display their talents, and while the album doesn't break any new ground it nevertheless is a vivid, personal and entirely enjoyable portrait of a jazz family.

Side 2, devoted to the Freemans, is even more revealing because the parallels between the two saxophonists are easier to chart. Von Freeman's sound has never been easy to categorize. He opens with a swaggering tribute to the late saxophonist Gene Ammons entitled "Jug Ain't Gone." But Von's tone, especially his habit of bending the pitch, is distinctly his own. He's particularly at home warming up to the ballad "I Can't Get Started," where his tone is fat, sensuous and supremely confident.

Chico Freeman is no silent partner in this collaboration. Many of Chico's recordings have succeeded simply because he's a master at fusing traditional and avant-garde approaches. There are times on his own recordings, and especially on this one, when his father's influence, indeed his presence, is felt. But there also are those moments when the spirit of John Coltrane looms large. That's especially true of "Tribute to Our Fathers," in which Chico and his frequent companions, bassist Cecil McBee and pianist Kenny Barron, embark on a challenging and typically bold excursion, that brings the album to a vibrant and undeniably contemporary close.

Wynton Marsalis and Chico Freeman get a chance to collaborate for the first time on Chico's latest album, "Destiny Dance." Here, too, are examples of jazz past and present coexisting, notably Freeman's lovely bass-clarinet tribute to Duke Ellington and Thelonious Monk entitled "Embracing Oneness." The clarinet and Bobby Hutcherson's vibes make for a wonderful array of haunting moods and textures.

Marsalis also finds the bass clarinet a fitting companion on the muted and impressionistic "Crossing the Sudan." But the sparks generated by the title track and "C & M" best reveal his technical virtuosity as well as an adventurous spirit that bodes well for jazz -- past, present and future. THE ALBUMS: "Fathers and Sons" (Columbia FC37972) and "Crossing the Sudan" (Contemporary 14008). THE CONCERT: Wynton Marsalis performs from noon to 5 at the Kool Jazz Festival in the Eisenhower Theater, with Dizzy Gillespie, Herbie Hancock, Tony Williams and Ron Carter; the Chico Freeman Group performs 7 to midnight.