None of this is to say that folk jazz has emerged full blown from the foreheads of Haden and Metheny. There have always been certain folk elements in jazz, but two important musicians, Ornette Voleman and Charles Mingus, both of whom Haden has been associated with - directly, in the case of Coleman, and indirectly with Mingus, made use of folk elements in the compositions. Coleman based some of this freest excursion of Medicali-type lines, and Mingus made considerable use of black folk materials. (Mingus, of course, had an influential effect on just about every jazz bassist to follow him in pioneering the bass as a solo instrument.)

Coming from the other side of the hybrid, Pat Metheny is perhaps best known to a general audience for his work with Joni Mitchell. And it could be said that it was Mitchell's collaboration, as a singer-songwriter with strong folk roots, with Charles Mingus that inaugurated the genre as a whole.

The type of musician likely to record on ECM is characteristically reluctant to concede that his music is jazz at all and, after a close listen to much of the label's product, one is tempted to say that the manner in which folk motifs are used in this new style of music has much more in common with the way in which European art-music composers from Dvorak to Bartok made use of the folk music of Slavic cultures.

The typical ECM record is typified by immaculate Deutsche Grammophon-style production and a kind of pure, unrelenting lyricism. Two musical qualities historically associated with jazz are often conspicuously absent from ECM recordings, namely that propulsive driving swing that so often characterizes black American music and that sense of suggestive grit that gives jazz its most sensual textures. (This is in a sense ironic since the twin forebears of the style, Coleman and Mingus were instrumentalists known for the strong vocal quality of their playing.)