A groundbreaking album and an early Jazz Fusion release. Miles expands on his use of electric instruments first explored on his In A Silent Way from earlier in 1969. These 6 tracks were recorded in August of 1969. With a band that included a five piece rhythm section of two bass players, two drummers and a conga player most tracks are rhythm heavy. Two electric piano players, sax, clarinet, and electric guitar join Miles’s trumpet in the mix. Much editing by producer Ted Macero was used including splicing, tape loops, reverb and echo effects. “Pharos Dance”(20mminutes), “Spanish Key”(17 minutes) and “Miles Runs The Voodoo Down”(14 minutes) are the ones I liked best with a driving rhythm throughout. The title track at 27 minutes seems a bit disorganized. “John McLaughlin” is a 4 minute piece featuring McLaughlin’s electric guitar. The ten minute “Sanctuary” is a more mellow composition featuring Wayne Shorter’s sax. The album won a Grammy Award in 1971 for Best Jazz ensemble recording and is Davis’s best selling recording. He would continue to play this Jazz Rock Fusion style for the next five years.