For devotees of Miles Davis’s so-called “electric period,” the full release of the music recorded live in December 1970 at the Washington, DC club The Cellar Door has long been something of a holy grail. A healthy sampling was released in 1971 on Live-Evil providing evidence that more of this sound existed. The possibility that more from this lineup was in the vault gave hope to at least many of the baby boomers I keep in touch with. With the release of the 6-CD box set The Cellar Door Sessions 1970, all the anticipation is rewarded beyond measure.

The music on these CDs has continued to evolve even from the heights of the four extraordinary studio LPs Miles Davis recorded in the previous 18 months: In a Silent Way (rec. February 1969), Bitches Brew (rec. August 1969, double LP) and A Tribute to Jack Johnson (rec. April 1970). Besides being a live date, the ensemble here was made up of a different cast of characters. Those earlier “electric” albums are masterpieces partly because the musicians were pushed to the extremes of their creative artistry, they were of a caliber that could provide surprises, and because producer/collaborator Teo Macero took the session tapes and chiseled into form the rehearsed tunes and hours of spirited improvising.

Here, on the live dates, the musicians fill hour-long sets by stretching out some of the material previously worked out in the studio. Teo is at the controls again, manning the recorder at the club, but this time without his post-session work of crafting the material into a collaged suite. This is a strictly live recording, excellent sound quality, with only a few insubstantial edits.

Miles is forging something extraordinary here. Without concession to audience expectation, he’d been using club dates to grow his sound. Never one to repeat himself, his concept by this time clearly was not to present tunes. While the repertory across the six CDs consists of eight composition—10 sets were recorded over four nights and six complete sets are presented here—each piece is a springboard from which to invent, unfettered by the restraints of chord changes or the need to serve a melody. Miles is leading the ensemble into free territory. There’s no room for show biz slickness or pandering for dramatic effect. Miles is a patient listener and steps back to allow the other soloists to ignore 12-bar convention and reach full articulation. This is artistry of the highest order, creative expression at its most sophisticated.

The one-hour sets appropriate elements from funk and rock, but this is an entirely new uncategorizable beast—an amalgam of funk, rock and traditional jazz. The music is unlike anything. Comparisons are futile. It’s even a stretch to say the music is an extension of what Miles himself had been creating in the studio. It’s essentially a small group format, but is as far from conforming to a traditional jazz audience’s expectations as the listening experience at the Fillmore East is from that at the Village Vanguard.

Occasionally, a head statement will be played in unison by Miles and saxophonist Gary Bartz, with the rest of the band filling in the chordal progression, but that melodic phrase is merely a concession to the audience’s need for something familiar to tether their experience to.

Keith Jarrett’s playing on Fender Rhodes is perhaps the greatest prize from the set. The timbre of the electronic keyboard might grate some listeners after a while, but his explorations transcend the funk/rock indications defined by Jack DeJohnette’s solid 4/4 time-keeping and electric bassist Michael Henderson’s precise vamps. Jarrett’s keyboard utterances push into territory too colorful to be constrained by pulse. When the other musicians drop out to allow his cadenzas to go where they may, particularly during four “Improvisations,” Jarrett takes advantage, maximizing the electronics to novelty effect, but more importantly, using the full range of the keyboards (he’s also playing a Fender electric organ at times). His improvisations have more complicated intentions than the prescribed boundaries of the tunes’ formal structure. When freed from the rigor of the funk/rock requirements, there’s a chance for the expression of more complex emotions and an exploration instead of a proclamation.