Despite a promising start, the relationship between jazz and television has never fulfilled its potential. But, 30 years after the heyday of such important and icon-packed British jazz programmes as Jazz 625, the music appears to be staging a television comeback with the recent live performance show Jazz 606, and Jazz Heroes, the new six-part Channel 4 documentary series, kicking off tomorrow.

If you're looking for the lowdown on such legends as Bix Beiderbecke, Billie Holiday or jazz king Louis Armstrong, you will be disappointed. Although Jazz Heroes focuses on a different musician each week, it is not a collection of straightforward profiles of leading figures in American music. The programme makers' agenda is ambitious: to offer an overview of the emergence of ''modern'' post-war jazz, using material from the vaults plus interviews, analysis, and demonstrations from contemporary musicians (since all those featured are dead).

The first programme concentrates on pianist Thelonious Monk, whose ahead-of-his-time playing was hard for even the most broad-minded of ''modernists'' to get to grips with. Jazz Heroes portrays a man who created his own musical world and was totally indifferent to responses his playing provoked. Among the musicians who dissect and discuss Monk's compositions and forceful, percussive, and dissonant piano style is young British pianist Julian Joseph.

Trumpeter Dizzy Gillespie's role as one of the architects and popularisers of bebop is outlined in the second instalment. His abiding influence is reflected in the contributions from the trumpeter he called his ''musical son'', Jon Faddis, and saxophonist Jean Toussaint.

Two of jazz's most significant losses during its ''modern'' age - John Coltrane and Wes Montgomery - are also honoured. Coltrane, an avant-garde tenor saxophonist, had his roots in rhythm and blues and bebop - one of his earliest jobs was playing in Dizzy Gillespie's big band. His short (he died aged 40 in 1967) troubled life and restless search for musical expression are explored in the programme which features homages from such young players as Joshua Redman. Electric guitarist John Leslie ''Wes'' Montgomery, who worked himself into an early grave at 45, just three years after Coltrane, is remembered by George Benson as a generous but perfectionist player.

Given Jazz Heroes' line-up so far, the choice of singer Ella Fitzgerald and baritone saxophonist Gerry Mulligan to complete the bebop-dominated sextet seems surprising, since both are associated with a broad range of jazz music. In the late 1940s, however, Fitzgerald sang for two years with Dizzy Gillespie's bebop big band and developed an awesome and unique scatting technique, made accessible through her swinging style and clear voice. She is remembered in the programme, by admirers like Dee Dee Bridgewater, as a great jazz singer.

A teenage Gerry Mulligan - the only white jazzer to make the heroic grade - started out in bop bands in the mid 1940s, but soon gave up bebop in favour of a less frenetic type of jazz which came to be known as ''cool''. An accomplished composer and arranger, Mulligan explored chordal textures and harmonies in his writing, and in his bands he experimented with different combinations of instruments. As the jazz world's foremost exponent of the baritone sax, he shot to fame with the pianoless quartet which featured his clever, trademark, counterpoint underpinning Chet Baker's wistful trumpet. He may be a surprising sixth member of the Jazz Heroes line-up, but, throughout his 69 years, Mulligan remained a musical groundbreaker deserving of more attention than he usually received.

n Jazz Heroes, Channel 4, Sunday at 7.30pm.

n A book, Jazz Heroes (Collins & Brown, #17.99), by John Fordham, has been published to accompany the series.