In the 1940s BeBop performers such as saxophonist Charlie "Yardbird" Parker, pianist Bud Powell and trumpeter John Birks "Dizzy" Gillespie helped to shift jazz from danceable pop music to more challenging "musician's music. However, its main innovators were saxophonist Charlie Parker and trumpeter Dizzy Gillespie. BeBop had established itself as vogue by 1945, but not without contraversy.
The bebop musicians refused to be relegated to the role of entertainer, often behaving in temperamental or "difficult" ways. They sometimes even turned their backs on the audience. The entire attitude of bebop seemed to be "I am playing for myself and for the other musicians who are playing with me. Your listening is purely coincidental" (M. Bowden).
Free jazz and avant-garde jazz, are two partially overlapping subgenres that, while rooted in BeBop, typically use less compositional material and allow performers more freedom. Free jazz uses loose harmony and tempo, while Avant-garde jazz has more ‘rules’. Latin jazz has two main varieties: Afro-Cuban and Brazilian jazz. Afro-Cuban was played in the U.S. directly after the bebop period, while Brazilian jazz became more popular in the 1960s and 1970s.
In the late 1960s, the hybrid form of Jazz-Rock fusion was developed. Notable artists of the late 1960s and 1970s jazz and fusion scene include: Miles Davis, Chick Corea and Herbie Hancock. While it is arguable that this Fusion benefitted the evolution of Rock, few of its influences remain in today's Jazz.
In the 1980s, the jazz community shrunk dramatically and split. A mainly older audience retained an interest in traditional and "straight-ahead" jazz styles.
At the same time, other practitioners and fans explored experimental jazz, and musician fused jazz idioms with contemporary popular music genres such as disco (acid jazz) or rap (jazz rap).
Understanding jazz is often difficult and those who play jazz have often expressed the feelings that jazz should remain undefined, Jazz should be felt. "If you gotta ask, you’ll never know" (Louis Armstrong).
Steve Shorter: February 2007
Sources: Wikipedia, Piero Scaruffi: History of Rock Music, Encyclopedia Britannica 2002, BBC Online – Music, M.Bowden, Jazzitude: History of Jazz.
Thanks for the images, go to: BennyGoodman.com; CharlieParker.com; Scott Joplin by Charles K Moss; Miles Davis from Musicteacher.com; Herbie Hancock from Wikipedia; Jazz Image and Louis Armstrong from Yahoo! Images.
The History of Popular Music Index 
