John Lennon/Plastic Ono Band (An eight-disc,six CDs, two Blu-rays) Ultimate Collection chronicles the 1970 sessions, which started shortly after the Beatles disbanded, and throws the era into new light and perspective. And it’s still a cathartic and invigorating listen.

That original album, in a new mix,. The demos, outtakes and raw studio takes here drive home these points. At turns more raw and less sharpened than the familiar versions, these early and discarded run-throughs of album tracks and singles like “Give Peace a Chance,” “Cold Turkey” and an especially tough “Instant Karma! (We All Shine On)” demo are nonetheless jagged.

John applied the techniques he learned. “Mother,” the album’s opening track, ends with throat-shredding howls that Lennon worked himself up to in the alternate takes featured on The Ultimate Collection. And in the more spacious “Elements Mix” of “Well Well Well,” his cathartic screams seem to pierce even deeper.

Included past Beatles associates Ringo Starr, Phil Spector and Klaus Voormann in various roles. A disc of tossed-off jams, recorded during the sessions between takes, includes early rock ‘n’ roll staples like “Johnny B. Goode” and “Ain’t That a Shame” plus snippets of Beatles songs “Get Back” and “I’ve Got a Feeling.”

Similarly, the fly-on-the-wall appeal of “The Evolution Documentary” disc charts the progression of songs as well as Lennon’s hurdles, instructions and determination as he was making the album. He references both the Beatles and McCartney as he strains to nail a guitar tone and asks for advice from his collaborators.