MusicXML scores for euphonium by The Modern Jazz Quartet

The Modern Jazz Quartet (MJQ) was a jazz combo established in 1952 that played music influenced by classical, cool jazz, blues and bebop. The Quartet consisted of John Lewis (piano), Milt Jackson (vibraphone), Percy Heath (double bass), and various drummers, most notably Kenny Clarke (from 1952 to 1955) and Connie Kay (from 1955 to 1994). The group grew out of the rhythm section of Dizzy Gillespie's big band from 1946 to 1948, which consisted of Lewis, Jackson, and Clarke along with bassist Ray Brown. They recorded as the Milt Jackson Quartet in 1951 and Brown left the group, being replaced on bass by Heath. During the early-to-mid-1950s they became the Modern Jazz Quartet, Lewis became the group's musical director, and they made several recordings with Prestige Records, including the original versions of their two best-known compositions, Lewis's "Django" and Jackson's "Bags' Groove". Clarke left the group in 1955 and was replaced as drummer by Kay, and in 1956 they moved to Atlantic Records and made their first tour to Europe.

Under Lewis's direction, they carved their own niche by specializing in elegant, restrained music that used sophisticated counterpoint inspired by baroque music, yet nonetheless retained a strong blues feel. Noted for their elegant presentation, they were one of the first small jazz combos to perform in concert halls rather than nightclubs. They were initially active into the 1970s until Jackson quit in 1974 due to frustration with their finances and touring schedule, but re-formed in 1981. They made their last released recordings in 1992 and 1993, by which time Kay had been having health issues and Mickey Roker had been his replacement drummer while Kay was unavailable. After Kay's death in 1994, the group operated on a semi-active basis, with Percy Heath's brother Albert Heath on drums until the group disbanded permanently in 1997.