The quartet of David Murray, Julius Hemphill, Oliver Lake, and Hamiet Bluiett, despite their seemingly odd rhythm section-less configuration, ranked as one of the major Avant-Garde Jazz groups of the late '70s and '80s. They seamlessly combined razor-sharp riffing, dense, choir-like arrangements, and empathic four-way improvisation. Each member brought a strong background in blues and R&B, which served to ground even their most frenzied extrapolations. It also helped that each member, especially alto saxophonist Hemphill, made distinguished contributions in the writing department. The group came into wider recognition in the mid- to late-'80s with a series of major-label LPs (including a well-received Ellington tribute) before Hemphill departed in 1989. They've continued in his absence, adding percussionists and other guests. Recent albums, however, haven't always met the high standards of their earlier ones.