There are some takes that don’t pass the test of time. For centuries, the human race believed that the sun revolved around the earth. We all got over that. People thought tomatoes were fatal to eat, leeches were quality health care, Lee Harvey Oswald acted alone. Read anything published about cocaine in the 1970s and you will find the word “non-addictive.” And when Radiohead released Amnesiac in the summer of 2001, many fans thought it was infinitely better than Kid A. It rocked harder. Sharper tunes. Wider emotional range. The ultimate one-two punch: Radiohead made two space-rock masterpieces at the same sessions, and they saved the best stuff for the sequel.

Over the years, the Kid A legend just keeps growing — Radiohead’s most legendary classic. But Amnesiac has become weirdly underrated, overshadowed by its more famous sibling, to the chagrin of diehard Amnesiacs. Radiohead revisit these sessions in Kid A Mnesia, a stunning collection making the case for both albums as twin halves of the same musical statement. Kid A Mnesia tells the whole insane story over three discs — both original albums plus Kid Amnesiae, a collection of outtakes, B-sides, unreleased experiments. It’s the sound of crazed geniuses running wild in the studio, ready to try anything. Result: two classics, with plenty of brilliant music left over.

The premise was simple: wildly successful rock stars decide to rip it up and start again, trading their guitars for synthesizers they don’t quite know how to play. As Kid Amnesiae shows, they were overflowing with ideas, with a “what does this button do?” spirit. And in classic Radiohead style, they drove each other mad, doing every tiny detail the hard way. As Thom Yorke confessed in Rolling Stone, “I made everyone’s life almost impossible.”

One of the new highlights: “If You Say the Word,” a previously unheard gem that got shelved. (Jonny Greenwood dismissed it as “too tasteful.”) Yet it’s Radiohead at peak strength, with Thom Yorke contemplating different kinds of betrayal over eerie synths. “Follow Me Around” is a cult favorite that’s never had a proper studio release, though they’ve touched on it a few times live — a paranoid acoustic kiss-off that dates back to the OK Computer sessions, with Yorke sneering, “See you on the way back down.” It’s hard to imagine any other band letting songs this great slip away. There’s retooled versions of lost B-sides like “Fast Track” and “Fog.” Kid Amnesiae has echoes of the original albums — the “Motion Picture Soundtrack” harp glissandos, the “How To Disappear Completely” strings — like fragments of a nightmare you can’t shake off.

“Pulk/Pull (True Love Waits Version)” is a full-on electro-glitch version of the longtime highlight — one of Radiohead’s most beloved songs—though it didn’t get an official studio release until they revived it in 2016 for A Moon Shaped Pool. This is one they should have released at the time. It whirs with ominous synths and Fender Rhodes piano, a la “Everything In Its Right Place.” “The Morning Bell” was the only tune from the sessions that appeared on both albums, so it’s fitting to hear a third approach on Kid Amnesiae, an instrumental full of mournful carnival organ.

Kid A and Amnesiac were the first big-deal rock albums of the Napster era, so fans around the world already knew much of the material from live MP3s. When Kid A dropped in October 2000, it was a mystery why Radiohead seemed to be holding back their strongest new songs. No “Knives Out”? No “You and Whose Army?” No “Pyramid Song,” which we all knew as “Egyptian Song”? The arguments just heated up when Amnesiac dropped in the summer of 2001. Amnesiac was tougher, more punk, flaunting the guitar power of Jonny Greenwood and Ed O’Brien. One highlight, “I Might Be Wrong,” hijacked the Allman Brothers, while “Knives Out” sounded like every single Smiths song thrown into a juicer. While Kid A went abstract, Amnesiac showed off the rock & roll masters Radiohead had always been, however reluctantly.

These days Amnesiac is ripe for reappraisal. Last year, in Rolling Stone’s comprehensive poll of the 500 Greatest Albums of All Time, the voters put Kid A in the Top Twenty, while Amnesiac didn’t even make the cut. (The list also had OK Computer, The Bends, and In Rainbows.) Ironically, Kid A sits on the list right behind Kendrick Lamar’s To Pimp a Butterfly, which samples “Pyramid Song” from Amnesiac. The second half often gets reduced to a mere footnote in the Kid A story — Bridesmaid A. But it’s a landmark in its own right. 

The whole Kid A Mnesia project looked like a commercial disaster waiting to happen back then. But both these albums were gigantic commercial blockbusters — hell, you could go ahead and call them pop hits. Kid A debuted at Number One in October 2000, and it turned out to be the right ice-age-coming soundtrack to the dystopian endgame of Y2K, as the Supreme Court blocked the state of Florida from counting votes and awarded the presidency to the guy who lost the election. It was the start of a new century full of “this is really happening” disasters. Kid A Mnesia isn’t just a monument of Radiohead’s bravest, boldest music — it’s a tribute to keeping the creative fires burning even in the coldest of times.