Jazz-rock fusion or, often, simply “fusion” emerged in the late 60s as the child of many mothers. Characterized by electric instruments and rock rhythms, it could be loud and fast, but just as likely, could be melodic or lyrical or funky. The Charles Lloyd Quartet, the Gary Burton Quartet, Tony Williams Lifetime and the Joe Zawinul Group all showed elements of what became the best-selling strain of jazz in the 1970s. And once again, of course, Miles Davis was in the center of things.