In late 1971, when an enraged fan pushed Frank Zappa off the stage at London’s Rainbow Theatre, leaving him with a grab-bag of injuries, it could have kick-started a bleak creative period. (At the very least, no one would have blamed him for taking a really long break.) Instead, the composer—bound to a wheelchair for almost a year—took the opportunity for an invigorating reset, emerging with a massive “electric orchestra” devoted to densely layered jazz-fusion. (That 20-piece band recorded two albums and played a handful of gigs, before Zappa scaled down for the 10-member Petit Wazoo tour.) The Zappa estate, sifting once more through the late artist’s massive vault, has now released the definitive warts-and-all portrait of that prolific era: live cuts, alternate mixes and previously unheard takes, as well as session demos from keyboardist George Duke and Dolby Atmos versions of both Waka/Jawaka and The Grand Wazoo. There are surprises everywhere: The alternate take on barnburner “Big Swifty” rivals the original in proggy chaos, with solo after solo on electric piano, drum set and squealing trumpet. Elsewhere, a heavier “Eat That Question” hinges on a cowbell-coated drum groove and funkier electric piano. But the most revealing moments are the Duke tracks—raw, rock-leaning approaches to the jazz-soul solo tunes (“Love,” For Love (I Come Your Friend))” he released in the mid-1970s. Like most of the label’s deep dives, this one is essential.