Fission — not fusion — is the right word to describe the music on these six CDs, at least according to my dictionary: "a cleaving of parts; the splitting of an atomic nucleus resulting in the release of large amounts of energy." Nothing in these recordings, made by Miles Davis during his most radical, electric-funk era, from 1972 to 1975, moves in consort to a fixed resolution: saxes, guitars, tumbling percussion; even Davis' commanding gales of trumpet. Compared to Bitches Brew, his defining 1969 rupture with modal and hard bop, Davis' 1972 LP On the Corner and the sessions that followed were amplified wartime, reflecting his obsessions with extreme blackness (Jimi Hendrix, Sly Stone) and the violent blurring of tone and noise in Karlheinz Stockhausen's compositions. Polyrhythm is all, even in the convulsive solos and melodic shorthand overhead, later edited and sequenced for release by producer and proto-mix-master Teo Macero. The players come from disparate worlds: R&B (bassist Michael Henderson, guitarist Pete Cosey), post-Coltrane blowing (saxophonists Dave Liebman and Sonny Fortune), the near East (tabla player Badal Roy). But the true star of pieces like the epic, unedited take of "On the Corner," the avant-Trinidad of 1973's "Calypso Frelimo" and 1974's furious, previously unissued "What They Do" is the P-Funk-like momentum of the musicians. Even Davis' long, aerated eulogy to Duke Ellington, "He Loved Him Madly," moves in insistent, implied time. The light funk ballad "Minnie," from Davis' last '75 session before he temporarily retired due to health and drug problems, points the way to his pop-jazz records of the Eighties — as if he knew how far out he'd gone and didn't expect to return.