Jazz fusion (sometimes referred to simply as Fusion) is a musical genre that loosely encompasses the merging of jazz with other styles, particularly rock. It basically involved mixing the concepts and philosophy of jazz with the electric instruments of rock, and rhythmic structure from African-American popular music, both "soul" and "rhythm and blues".
Fusion had its roots in the late 1960s but really began to develop in the 1970s as established jazz artists such as Miles Davis Julian "Cannonball" Adderley, Larry Coryell and Jeremy Steig formed bands using instruments such as electric guitar, bass guitar, and electric piano. Shortly, others began incorporating synthesizers such as the minimoog joining forces with more avant garde players who had also begun incorporating electronic sound in the wake of the "classical" avant garde.
At the same time, rock and African-American popular musicians had begun moving beyond the short "radio single" song format and incorporating elements of jazz-like extended instrumental improvisation. Michael Bloomfield and Paul Butterfield, both young white blues musicians, recorded extended versions of Adderly's "Work Song" and a modal improvisation, "East/West" as early as 1966-67; other groups, particlarly those based in San Francisco (Santana, Grateful Dead, Jefferson Airplane) and in the U.K. (Cream, King Crimson, Pink Floyd) also performed, and eventually recorded, both extended improvisations on short song forms, and longer, multipart compositions.
Jazz artists, in the wake of developments in pop music, also began using the recording studio, with improved editing, multitrack recording, and electronic effects capability, as a adjunct to actual composition and improvisation. Davis' "Bitches' Brew", (a cornerstone recording of the genre) for instance, features two "extended" (more than 20 minutes each) compositions which were never actually "played" straight through by the musicians in the studio; instead, musical motifs of various lengths were selected from recorded extended improvisations, and edited together into a musical whole which only exists in the recorded version.
Newer artists, such as Stanley Clarke, Chick Corea and Joe Zawinul also became involved in the developing scene. Musical barriers broke down further (to the continued horror of jazz purists) as musicians who had first established themselves as rock artists such as Jeff Beck began to experiment with the fusion form.
While jazz fusion is sometimes lampooned as being pretentious and overcomplicated - not unlike its cousin, progressive rock (rock meets classical music) - it has helped to break down boundaries between different genres and led to developments such as acid jazz. For the most part the genre has been subsumed into other branches of jazz and rock, but some traces of the form remain.
(please add to list in alphabetical order)