"You've got to get in to get out," Peter Gabriel declared, over and over, in Genesis' epochal "The Carpet Crawlers."

A highlight of 1974's The Lamb Lies Down on Broadway — Gabriel's final album with the prog giants — the track is drenched in philosophical and religious symbolism, redolent of a spiritual pursuit. A mystical staircase stretches into the firmament, and the eerie "crawlers heed their callers."

If that sounds maximum heady, it's because it is. And almost half a century later, Gabriel sang a nearly identical line. "Stuff coming out, stuff going in/ I'm just a part of everything," he announces in "i/o" — the title track to his album of the same name, which stands for "Input/Output," dropped Dec. 1 after a 21-year wait.

Not all critics were taken with that turn of phrase. But despite its simplicity, coming from Gabriel, it's profound.

Listening to Gabriel's inimitable body of work — whose cerebral art-pop captivated a generation, and unforgettable videos brought MTV to its knees — you get the sensation of widening the aperture, of considering an eternal timeline, of surveying and striving to transcend human limitations.

Like his past classics — the four eponymous albums, his 1986 knockout So, its 1992 dark-horse followup Us — i/o connects not just due to its vast purview, but because of Gabriel's gigantic, ever-beating pop heart.

The ballads, like "Playing for Time" and "So Much," are magnificent, showing how Gabriel can ably occupy an elder-statesman role and project gravitas that way. But so are the perky, uptempo numbers a la "Sledgehammer" of yore. "Olive Tree," with its ebullient, Graceland-like horn blasts, suggest Gabriel preserving the best parts of the '80s charts, holding them in the light, and discarding the rest.

Once you come out of i/o, you go back in: Gabriel released the album in two simultaneous, slightly different forms, dubbed the "Bright Side Mix" and "Dark Side Mix." As soon as you've finished your journey, you're asked to undertake it again, through an alternate series of corridors and halls.

Refractory, self-referential, mold-breaking, primevally moving — i/o ticks all those boxes. Here are five ways it adds to the six-time GRAMMY winner's discography.

Despite Its Piecemeal Release, It Flows As A Whole

If these songs seem familiar, that's because they are: last January, Gabriel began releasing one new single per every full moon, with an attendant, alternate mix on the new moon.

This one-by-one approach might have risked blunting i/o's impact, if the finished product didn't flow so incredibly well.

From opener "Panopticom" to closer "Live and Let Live," i/o ebbs, flows, and breathes: if you've been following these songs track by track, you're missing out if you don't behold it as a complete song cycle.

His Voice Is Still A Force Of Nature

By 73, many vocalists find their instrument diminished — yet, Gabriel's has aged like wine. Rather than stripping away its layers, the years have added ever more weight and body to his baritone.

A creamy center, with a biting edge of yearning and inquiry — this is just as we remember Gabriel's pipes, but they're arguably even more satisfying today.

Sonically, The Decades Paid Off…

Some legacy artists toil and toil on a comeback record for many years — and the result is still, paradoxically, a tad half-baked.

This is not the case at all with i/o — you're unlikely to hear an album this aurally detailed and mesmerizing for a while. Which doesn't mean it's overly commercial or slick: it means it's meticulously crafted, full stop.

…And He Didn't Spoil The Stew

Sad to say, there's another extreme that records of this ilk can fall into — becoming overproduced, overly teeming, terminally busy.

For how lush and expansive i/o is, there's a tremendous amount of space; nothing feels superfluous. That said, if you do wonder how these tunes might come across with something added or excised, the alternate mixes are right there to quench that curiosity.

There's (Hopefully) More On The Way

Yes, Gabriel is the consummate perfectionist — he called himself that to the New York Times.

"I'm a tinkerer," he elaborated. "So there's always a diversion. I've never had trouble — touch wood — with musical ideas. But getting to a point where I think there's a lyric that I'm happy with — that has been harder for me."\
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That being said, Gabriel doesn't foresee i/o being old enough to drink before the next one arrives.

In the same interview, he cited a "brain project" in the works, with "a lot of stuff in the can" — including a track called "What Lies Ahead," which he performed a number of times in 2023 and almost ended up on i/o.

Lucky us that a musical hero of past generations is still diamond-sharp. And that after so many years of Gabriel soaking up the input, his output flows freely again, sans resistance.

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