Gabriel’s final album with Genesis, the 1974 double-LP The Lamb Lies Down on Broadway, was born during a time of pain and confusion. Following the tour for ’73’s Selling England By the Pound, the classic quintet retreated to the dilapidated rehearsal house Headley Grange, where they hoped to foster chemistry by writing and living together away from real-life distractions. Unfortunately, the distractions were endless: The rat- (and possibly ghost-) infested house did little to spark their creativity, and Gabriel was forced to leave and tend to his then-wife, Jill, who was dealing with problems related to her pregnancy. With their frontman sidelined, the remaining four members plunged forward by writing mountains of instrumental bits, most of which were worked out by the trio of Banks, Collins, and Rutherford. Upon returning, Gabriel stunned the band by demanding to write all the lyrics, which he hoped to fashion into a Pilgrim’s Progress-styled concept focused on a spiritual journey; this ultimately became the surreal tale of Rael, a New York City delinquent who finds himself battling terrifying creatures in an alternate world, all while trying to rescue his brother John.

Just before the band started recording this ambitious concept album, Gabriel temporarily quit — aiming to collaborate with The Exorcist director William Friedkin on a screenplay. But once that project fizzled out, the frontman sauntered back to his bandmates, who now realized Gabriel’s days were probably numbered. They were, of course: The singer announced his departure in 1975, following their massive (and often disastrous) Lamb tour. But what a way to go out — this 94-minute sprawl encompasses all of the quintet’s idiosyncrasies and strengths: muscular, riff-based rock (the iconic title-track, the shape-shifting “Back in N.Y.C.” and “In The Cage”), delicate balladry (“Cuckoo Cocoon,” “The Carpet Crawlers”), and batshit crazy prog (“The Colony Of Slippermen”). Sonic adventurer Brian Eno even sprinkles some magic fairy dust (or “Enossification”) on quirky linking bits like “Here Comes The Supernatural Anaesthetist.” The Lamb is the least accessible of all the Gabriel-era albums — and with its occasional lapses into ambient texture, it can be a chore to sit through all at once. But when it’s good, it’s goosebumps-down-the-spine good, change-your-fucking-life good — and it’s only bested by the definitive Genesis LP, Selling England By The Pound.