'It's feasible to argue that Evans was the most painterly of all jazz arrangers'

One can only speculate on how Miles Ahead must have sounded when it came out in 1957. Davis had enjoyed one previous alliance with orchestrator Gil Evans, for the aptly titled Birth of the Cool in 1949, but heroin and its consequences had consumed much of the trumpeter's time since then, against which background he had fretted over his artistic direction, tinkered with Third Stream music, chopped and changed sidemen, then settled for the trumpet/tenor sax-fronted quintet which eventually grew into the most balefully tough-minded small group of the decade.

Then came Miles Ahead. This was neither a big band record nor, conventionally speaking, an orchestral one, but a sort of ensemble hybrid of the two, both in instrumentation (French horns and flutes strop it out with drums and trumpets) and arrangement. There is very little riffing in Evans's scores and even less development of orchestral theme. In fact, it's feasible to argue that Evans was the most painterly of all jazz arrangers: a musician preoccupied with atmosphere, colouration, texture and shape above all other musical issues. Effectively, he treated his 16-piece brass- and wind-dominated ensemble as dabs on a sonic palette, floating them away from their rhythmic underpinnings in monumental cloud formations, which he'd allow to drift around for a while, apparently untethered, before snapping them back into line to swing in halting gusts behind the soloist's considered linear movements. The sound could be by turns thunderous, brittle, frosted and diaphanous all in the space of a few bars. Against such a backdrop, Davis only had to turn up and be himself to enlarge the scope of jazz language.

Miles Ahead still sounds to me like the best of the three major records, partly because the diversity of the material (ranging from Delibes to JJ Johnson) tests both Davis's and Evans's resources on a broad front; partly because Miles plays unreservedly throughout; and partly because, for such a refined record, the music cleaves closely to the raw stuff of the blues. Porgy and Bess is, by comparison, artistry of a more cultivated, less fundamentalist kind - listen to the retroussee version of "Summertime" - while Sketches of Spain finds Davis exploring the duende he felt he shared with the Hispanic world; it's still Miles music but Miles music in a state of heightened drama.

The relationship between Davis and Evans was one of the most artistically robust of the Modernist century; it can easily stand just about anything you care to do to it in terms of revision. And while there is actually no need to buy this elaborately packaged and annotated 6-CD set to hear the music, the monumental scale of the thing is not unfitting. What you get is the three great albums, the comparatively slight but likeable Quiet Nights, plus out-takes, rehearsal cuts, chit-chat, alternate masters and the odd unreleased fancy such as "The Time of the Barracudas", a 12-minute suite of incidental music for a play, which has its moments.