The Modern Jazz Quartet (MJQ) was an influential music group established in 1952 and for most of their long career composed of John Lewis (piano, musical director), Milt Jackson (vibraphone), Percy Heath (double bass), and Connie Kay (drums).
Initially a side project for personnel from trumpeter Dizzy Gillespie's hard-swinging big band, the MJQ gradually became a full-time endeavor and one of the more prominent jazz bands of the post-WWII era. Under Lewis's leadership they carved their own niche by specializing in an elegant, restrained music (touching on bebop, cool jazz, third stream and classical music) that used sophisticated counterpoint yet nonetheless retained a strong blues feel. They introduced several jazz standards, including "Django" and "Bags' Groove".
Initially active into the 1970s until Jackson quit due to creative disagreement and frustration with their busy touring schedule, the MJQ reformed intermittently into the 1990s.