Miles Davis, trumpet
Wayne Shorter, soprano sax 
Lenny White, Jack DeJohnette, and Charles Alias, drums
Bennie Maupin, bass clarinet 
Chick Corea and Joe Zawinul, electronic piano 
Harvey Brooks (Fender) and Dave Holland, bass 
John McLaughlin, electric guitar 
Jim Riley, percussion

The early use of electronic instruments can be heard in Miles Davis' Bitches' Brew. Dave Holland shares his bass role with Harvey Brooks who plays electric bass. John McLaughlin plays electric guitar, not necessarily new to jazz, and Joe Zawinul, Larry Young, and Chick Corea join in with electronic piano. Outside of the horn players--Wayne Shorter on soprano sax, Bennie Maupin on bass clarinet, and Miles Davis on trumpet--the ensemble is completed with percussionist Jim Riley and with three drummers, Lenny White, Jack DeJohnette, and Charles Alias. Like rock groups, Davis gives the rhythm section a central role in the ensemble's activities. His use of such a large rhythm section offers the soloists wide but active expanses for their solos. 

The title cut from this record offers a good example of how the soloists can interact with the rhythm section. They sometimes hold sustained lines in contrast to the rhythm section's activity and at other times they act as just another member of the rhythm section and add only punctuated statements. The harmonies used in this recording move very slowly and function modally rather than in a more tonal fashion typical of mainstream jazz. Each harmonic center appears almost frozen as the players, both independently and collectively, pull away from it only to return and reaffirm it. The home key is established more by insistence than by the traditional tonal chord relationships. The static harmonies and the rhythm section's collective embellishment create a very open arena for improvisation. The musical result flows from basic rock patterns to hard bop textures, and at times passages are even more characteristic of free jazz. The cut entitled "Spanish Key" offers a more direct example of how a fusion rhythm section can establish a steady rhythmic drive over slowly moving harmonies. The harmonic changes occur so seldom that they create major articulation points in the composition.