The Modern Jazz Quartet was laid-back long before anybody thought of the expression, and it stayed that way after it went out of currency. One of the few jazz ensembles to become widely loved outside the world of the modern jazz cognoscenti, it was also one of the longest lived. Eventually, after a 30-year career beginning in 1954, the band's tinkling, metronomic, glassily perfect music came to a halt in the mid1970s. However, it was restarted by public demand in the 1980s and continued until 1999. John Lewis, the co-founder and compositional guru, who died on March 29th aged 80, was a writer of haunting jazz themes and film-scores. He was also a pianist of fragility and patience in an instrumental world populated by pyrotechnicians.
An experimenter, his crossgenre forms predated contemporary music's open-handed swapping of idioms and methods by decades. He also confirmed that subtle arrangement - sometimes disapproved of in jazz circles - could make the difference between a specialised audience and a much wider one.
His soft chords and glancing punctuation, against the sinewy lines of the double-bass and the shuffle and distant rumble of the percussion, made MJQ music identifiable from the first bar - even if it also drove some hardcore jazz fans into the nearest bar - and it was that chamber-group sound, emphasising the new bebop's most elegant, baroque-like formal properties, and playing down its heat, that led the band to dominate jazz record sales in the 1950s and early 1960s.
John Lewis was classically trained and the MJQ's stately tempos, elegant counterpoint and borrowings from rondos and fugues testified to it. He also insisted on dinner jackets for the band and, wherever possible, gigs in classical concert halls and recital rooms rather than clubs - manifestations of his conviction that jazz was entitled to equal treatment and status with formal music.
He was born in La Grange, Illinois. His parents were divorced shortly after his birth, and he moved with his mother to Albuquerque to join his maternal grandmother and great-grandmother, who raised him after his mother died when he was four.
After high school, he studied anthropology and music at the University of New Mexico, but was drafted into the US army six months before completing his degree. After serving in a special services band in Europe during the second World War, he returned to university to finish his degree.
John Lewis, who had met the pioneering bebop drummer Kenny Clarke on military service in Europe, moved to New York after the war at Clarke's urging. Clarke's presence in Dizzy Gillespie's revolutionary post-war bop-influenced big band brought an offer to him too - and soon, his mix of bop's advanced harmonies, classical devices, and Count Basie's minimalist melodic approach brought him freelance work with Charlie Parker, Lester Young, Illinois Jacquet, Ella Fitzgerald, King Pleasure and others.
In 1952, the Gillespie band's rhythm section (John Lewis, Kenny Clarke, Ray Brown on bass) plus a Gillespie soloist, the Detroit vibraharpist Milt Jackson, began to record as the Milt Jackson Modern Jazz Quartet. But though it was to be a collectively run ensemble, it was John Lewis's interests that increasingly shaped its identity, and its success story became one of the most striking jazz has known. From 1957 he was also writing film scores - notably for Roger Vadim's Sait-on jamais? (1957), and Robert Wise's Odds Against Tomorrow (1959). He wrote music for ballets and symphony orchestras, stage plays and television documentaries. For almost a quarter-of-a-century he was musical director of California's Monterey Jazz Festival and from 1962 to 1965 was a leader of Orchestra USA, a hybrid band featuring jazz instruments plus strings and woodwinds. The MJQ, which broke up in 1974, was re-formed in 1983 for some lucrative Japanese gigs, and continued until Jackson's death in 1999.
Between 1985 and 1992, he was also musical director of the repertory American Jazz Orchestra. His academic work also took in Harvard and the City College of New York. In the late 1950s he had founded the Lenox School of Jazz, Massachusetts.
Throughout his life he remained as quiet and undemonstrative as his music. His compositions Django (1954) and Two Degrees East, Three Degrees West (1956) are still played by jazz musicians everywhere. Evolution (1999) was an album of solo recital and its follow-up emerged earlier this year to considerable acclaim.
John Aaron Lewis: born 1920; died, March 2001