Just three blocks uptown from the heaving bars and nightclubs of 52nd Street, the thoroughfare known as 'Swing Street', they met and conspired. There was John Lewis, 27, a thoughtful pianist-composer who had worked with Charlie Parker and Dizzy Gillespie, and would go on to form the Modern Jazz Quartet. There was Gerry Mulligan, the crew-cut baritone saxophonist who had written 'Disc Jockey Jump' for the popular swing band of Gene Krupa and was to lead one of the most influential jazz combos of the early Fifties. There was George Russell, 24, a music professor's son who, during a lengthy period in hospital with tuberculosis, had formulated a new system of harmonic principles that he would later publish as the Lydian Chromatic Concept of Tonal Organisation. And, most significantly, there was a 21-year-old trumpeter called Miles Davis.
A dentist's son from East St Louis, a scion of the black middle class, Davis had arrived in New York four years earlier - ostensibly to study classical composition at the Juilliard Conservatory, in fact to find Parker, Gillespie and the fount of modern jazz. He succeeded so well that he gave up his studies almost immediately, spending three years with Parker's band, until he could no longer stomach the great saxophonist's perennial unreliability and slipperiness over money. By the time Miles Davis met Gil Evans, he was ready to make his own move.
At 35, Evans was the senior of the group that convened in the apartment on West 55th Street - although his diffident charm made him seem beyond questions of age. (In his seventies, he would be found in London, collaborating with Sting and David Bowie.) The big bands of the swing era were music factories, machines that demanded regular maintenance and strict supervision - qualities entirely inimical to Evans's bohemian temperament. But he had found in Claude Thornhill an unusually constructive employer, who - even at the cost of his own commercial success - firmly encouraged his arranger's attempts to lead the ensemble away from the cliches of swing and into its own artistic territory.
Both Thornhill and Evans were inspired by unusual textures (Evans admired Ravel and Faure as much as he loved Armstrong and Ellington), so the band was expanded to include a pair of French horns and a tuba, while the saxophone section made use of a wide variety of auxiliary woodwind instruments, from piccolo to bass clarinet. Thornhill and Evans also shared a distaste for music that moved too fast: like other big bands, they played for dancers, but it must have been hard to do anything other than smooch to Thornhill's largely slow- motion repertoire, with its rich inner voicings and exotic detailing. Inevitably, such a band could not outlast the boom years of swing; when Thornhill came out of the US Navy in 1946 he reassembled many of his old sidemen, but when even Benny Goodman and Count Basie were feeling the economic pain, there wasn't much hope for an overmanned and idiosyncratic outfit such as his. Among musicians, though, his prestige was unusually high; normally contemptuous of commercial big-band leaders, they recognised a rare measure of altruism struggling against the odds in an environment which encouraged conformity.
It was certainly symptomatic of Thornhill's disastrous commercial judgement that in 1947, not long before the band met its end as a permanent unit, he allowed Evans to add arrangements of three Charlie Parker tunes - 'Yardbird Suite', 'Donna Lee' and 'Anthropology' - to the repertoire. Bebop was music for listening, not dancing, which was why it became the first form of jazz to avoid broad popularity. If dancers had trouble with the dark ballads normally favoured by the Thornhill band, they must have been tied in knots by Evans's attempts to retain the fleetness and angularity of tunes originally played by a skeletal bebop quintet, even though the tones and textures were fleshed out with the broader instrumental palette at his disposal. The single unresolved tuba notes ending two of the pieces were a clear indication of Evans's understanding of the elliptical weirdness of bebop, but were hardly the calibre of ammunition with which Thornhill could mow down the likes of Les Brown or Tommy Dorsey in the fight for public favour.
Davis had co-written 'Donna Lee', and it was when Evans came looking for the sheet music that the two met. Somehow, the aggressive young trumpeter and the serene older arranger recognised each other as a kindred spirit, and a crucial 40-year relationship began.
They were looking for something new. Jazz, since its early days on the streets of New Orleans, had been a music with a strong component of competitive machismo: the trumpeter Buddy Bolden could be heard, according to legend, 30 miles away on a clear night, while in Kansas City in the Thirties, the ethos of the 'cutting contest' had turned jam sessions into musical wrestling matches. Indeed, faster, higher, stronger could have been a motto for virtually all trumpeters before Miles Davis, all arrangers before Gil Evans. But these two were hearing something different: a music with deeper currents and softer, subtler colours, the product of a sensibility formed by factors other than strength and endurance. Davis, too, was a competitive man, but his superiority was not the kind established by toe-to-toe slugging. It could be expressed only in something far less mundane: the development of a style so cool as to render its owner beyond competition - untouchable, unknowable, invulnerable.
The place to start was with the sound and speed of the music, and it was here that Gil Evans made his contribution. He could structure music that was delicate without being effete, that could sing of the blues without needing to drench itself in sweat. Against that background, Davis could begin the true evolution of a voice that had found little room to grow within the brisk technical rigour and repetitive formal routines of bebop.
Evans had always liked the idea of writing for individual soloists: a concerto grosso approach evolved from Ellington's practice of forming a piece with specific sidemen in mind. His ambition to work with Louis Armstrong foundered on the indifference of the trumpeter's manager, while an approach to Parker fell victim to the saxophonist's unwillingness to concentrate. In Davis, though, he found the perfect voice - and an utterly sympathetic sensibility.
Their plan called for a scaled-down version of the Thornhill band, retaining as far as possible its wide range of pitch and timbre. In Davis's mind, the structure would mimic the divisions of a vocal quartet: bass, baritone, alto and soprano. A rhythm section of piano, bass and drums would support six horns: tuba at the bottom, then baritone saxophone, trombone and French horn in the middle, trumpet and alto saxophone at the top. Each horn had its own voice, separated by air and space but deployed with a flexibility that permitted many different combinations and contrasts.
The rhythm section - Lewis on piano, the bassist Al McKibbon, and the drummer Max Roach - came from bebop, bringing with them that idiom's rhythmic intensity. Joining Davis and Mulligan in the horn chairs were a young trombonist, Mike Zwerin; a French horn specialist, Junior Collins; and two graduates from the Thornhill academy, tuba-player Bill Barber and alto saxophonist Lee Konitz. Davis, in fact, had wanted Sonny Stitt, a gifted Parker disciple; for once, he had his mind changed - by Mulligan, who saw that Konitz's pale, translucent tone and oblique phrasing would provided a different sort of inner voice.
Since Evans was a notoriously slow worker, and each piece had to be tailor-made to fit the unorthodox instrumentation, it took them some time to assemble even a minimally adequate repertoire. Mulligan and Lewis pitched in with arrangements, while Davis took upon himself the tiresome burden of calling the musicians, organising rehearsals and hustling for gigs. In his first real shot at leadership, he was clearly making an effort to turn this unconventional outfit into a credible working proposition. Monte Kay, an agent who worked with many jazz musicians, eventually booked the nine-piece ensemble into the Royal Roost, a popular bop joint on Broadway, where it opened in August 1948, second on the bill to the Count Basie Orchestra, under a sign reading Miles Davis's Nonet: Arrangements by Gerry Mulligan, Gil Evans and John Lewis - an unusual form of billing which clearly reflected the band's unique selling point.
That first fortnight attracted the attention of some of the more inquiring minds among their fellow musicians. Basie himself listened hard, and is reported to have told Davis that the band's music was 'slow and strange, but real good'. Surviving transcriptions of radio broadcasts from the Royal Roost show a spirited and confident ensemble. The critics were less certain, although there was constructive interest from Pete Rugolo, the musical director of Capitol Records. A skilled arranger himself, having helped establish Stan Kenton's controversial 'progressive jazz' approach in the mid-Forties, Rugolo could not rush the band into the studio, since the American Federation of Musicians had instigated a recording ban which lasted through 1948. Since there was no other interest from booking agents, the project was put on hold and the musicians went off to earn a living by various other means - Davis turning down an offer to join Duke Ellington's trumpet section in order to freelance around the New York club scene. But in January 1949, the record ban over, Rugolo reconvened the nonet in a Manhattan studio for the first of three sessions that would change the sound of jazz for a decade and more.
The sessions were spread over a period of 15 months and, given the unpredictability of jazz musicians' lives, featured several musicians who had not taken part in the debut at the Royal Roost. Others who passed through included the drummer Kenny Clarke, the pianist Al Haig, the trombonist J J Johnson. Four titles were recorded at each of the three three-hour sessions, and six of the total of 12 pieces were released on 10- inch 78rpm discs: Lewis's arrangements of two bop classics, Denzil Best's 'Move' and Bud Powell's 'Budo'; Mulligan's swinging treatment of George Wallington's 'Godchild' and his own 'Jeru'; plus 'Boplicity' and Johnny Carisi's 'Israel'. Initially, public reaction was lukewarm; only Rugolo's enthusiasm kept the sessions coming. Gradually, though, musicians across America began to pay attention to the smooth, serene sound of this strange little band. After the power of the big bands, the raw freneticism of jump music and the high intensity of bebop, this new sound, with its porcelain surface, proposed an entirely different direction: disdaining obvious exertion and explicit emotional involvement.
Not everybody liked it. Dizzy Gillespie, for one, was ambivalent about the way it had discarded the emotional heat of his kind of jazz. 'It was a natural progession,' he admitted, 'because Miles had definitely come out of us, and he was the leader of this new movement. So it was the same music, only cooler. They expressed less fire than we did, played less notes, less quickly, and used more space, and they emphasised tonal quality. This music, jazz, is guts. You're supposed to sweat in your balls in this music. They sorta softened it up a bit.'
But for Davis, the music of Gillespie and Parker had been too complex for a mainstream audience. 'If you weren't a fast listener,' he said, 'you couldn't catch the humour or feeling of their music. Their musical sound wasn't sweet, and it didn't have harmonic lines that you could easily hum out on the street with your girlfriend trying to get over with a kiss.'
You could hear what he meant most clearly in Evans's work on a song called 'Moondreams', a commercial ballad which began in a gentle reverie but gradually accumulated an intense luminosity until, in the final measures, the rhythm section disappeared along with the tempo, the alto saxophone held a series of unearthly whistling high notes, the trumpet and tuba wandered beneath it, the trombone stuttered and each voice appeared to be acting in autonomy until the piece tapered away in a sort of constructive anti-climax. No rhetoric, no obvious virtuosity, not even any improvisation (although Evans's genius made the whole thing sound improvised). There had been nothing like it.
It took years for the nonet's effect to work its way through the system of American music. But a new generation was listening. In California, especially, young arrangers like Shorty Rogers and Marty Paich found the airy sound of the nonet to be in tune with the post-war mood of optimism, expansionism, modernism. When the results of all three sessions were compiled into an album, they called it Birth of the Cool. The cool world was here.
'Birth of the Cool' is available on CD and tape on Capitol Records.
Adapted from 'Miles Davis: The Man in the Green Shirt' by Richard Williams, with photographs by Herman Leonard, Dennis Stock, Jim Marshall and others, to be published on Thursday by Bloomsbury (pounds 18.99).