In late 1998, Summerteeth was basically finished. Wilco had been shuttling back and forth between the recording of this, their third album, and Mermaid Avenue, a collaboration with Billy Bragg built entirely on the skeletons of unfinished Woodie Guthrie songs. But the Reprise Records executives with the authority to pull the trigger thought something was missing from the record—something that might extend the band’s reach to alternative radio, which at the time was dominated by the likes of Matchbox Twenty and Third Eye Blind.

The band retreated to the studio to record an upbeat single, but the end product was curiously dark. In all fairness, “Can’t Stand It” doesn’t necessarily sound dark. It sounds so bright, in fact, that it practically chirps; it’s full of bells and chimes, adorned with a polished sheen and anchored by one of Jeff Tweedy’s most unshakeable melodies.

But just beneath the surface lurks unease. Tweedy is looking over his shoulder, vaguely paranoid about “speakers speaking in code.” Buoyant as the chorus is, he seems vexed: “No love’s as random as God’s love… I can’t stand it.” The outro is a blunt, repeated refrain: “Your prayers will never be answered again.” It would be hopelessly bleak if it didn’t sound so sunny.

Even with the record label hovering over the band’s shoulder, “Can’t Stand It” failed the Goo Goo Dolls test, sputtering on the radio stations it was meant to storm (it never charted). But the song nonetheless offered a glimpse into the artistic logic that would define the rest of the record. Summerteeth, which was released twenty years ago this week, is a rich, maximalist album that offers listeners a lot to chew on, but its defining constant is the anxiety of Jeff Tweedy—alternatively heartbroken and lovestruck, conciliatory and defiant, impassioned and indifferent, often in the same breath.

He is, in other words, deeply human. And Summerteeth finds him staring down personal demons in a way he never had before. The outro of “A Shot In the Arm,” where he sings, “What you once were isn’t what you want to be anymore,” feels akin to a dam breaking. Pointed, accusatory, but above all, just sad, that confessional approach sets the stage for even more emotive songwriting later, like the relationship-on-the-brink smolder of “At Least That’s What You Said” and the extended therapy session at the core of “Ashes of American Flags.”

The context of this, importantly, was that Tweedy was coming apart at the seams. According to music critic Greg Kot’s 2004 book, Wilco: Learning How To Die, touring had gradually been chipping away at him; as time away from his family accumulated, the grip of depression was tightening. “He was crying, a wreck, recording some of those songs,” drummer Ken Coomer told Kot. Tweedy’s anxieties have served as a fulcrum for plenty of seminal Wilco moments. The agonizing recording of Yankee Hotel Foxtrot—as it was captured in the essential documentary, I Am Trying To Break Your Heart—nearly destroyed the band, culminating in a split from their record label and the firing of Jay Bennett; 2004’s A Ghost Is Born arrived under the specter of a Tweedy rehab stint for depression and addiction to painkillers, which occurred just weeks before the album's release.

In 1998, though, this dynamic was new, and it was dramatically impacting Tweedy’s writing. In Wilco’s early years, Tweedy admitted to Kot, he rarely wrote verses down before recording (an approach later adopted by Lil Wayne). With Summerteeth, though, Tweedy began writing down lyrics, newly inspired by lyrical giants such as Leonard Cohen, Bob Dylan, and Patti Smith. According to the book, the band believed that the renewed focus was paying dividends artistically, but Tweedy was uneasy about the frankness of his songwriting. “When I got home and listened to that session, I didn’t want it to come out,” he told Kot. “I didn’t want people to have to sit through this, because I couldn’t sit through it.”

Tweedy wanted to mask the trauma in technicolor, Pet Sounds_-inspired pop, so he sought a partner in Jay Bennett, Wilco’s brilliant multi-instrumentalist, who would later be central to the turmoil on display in _I Am Trying To Break Your Heart. Bennett had been with Wilco from the start, but Tweedy told Kot that their chemistry really blossomed during the making of Summerteeth. “The task became: How to quiet the voice of despair that’s in those songs?” Tweedy said. “Because an album shouldn’t rub anyone’s nose into one person’s problems…That’s where Jay’s expertise in the studio came in. I felt I needed to bury those lyrics safely under glass.”

So Bennett got to work on the burial, stacking vocal harmonies and adding Mellotron, synths, banjo, strings, organ, tambourine—anything that might work. They smothered otherwise simple songs in studio flourishes, brightening them into pop confections without removing the soul at their core. As fruitful as their partnership was, it sharpened tensions with the band members they were sidelining. Coomer was unenthusiastic about the new dynamic. “The band was different,” he told Kot. “There really wasn’t a band, just two guys losing their mind in the studio.”

Turmoil aside, the result is gorgeous and multilayered, an album that embraces the vintage rock and roll foundation of its predecessor, 1996’s Being There, but substantially deepens its reach. Summerteeth only sporadically gestures at the alt country that characterized Tweedy’s first band, Uncle Tupelo, and the first few Wilco records. That sound certainly exists in the album’s DNA, but Summerteeth feels like a calculated move away from that world and into a new one.

This is clear throughout, and notably with “A Shot In the Arm,” which has the melodic instincts of Being There, but little of that album’s restraint. “Arm” is one of the band’s most beloved songs—funny, moving, and vital, careening to its conclusion with more urgency than anything Tweedy had written before. Later, “Pieholden Suite” combines three different movements into one song (an approach later adopted by Travis Scott). The first act, a piano-anchored waltz, swoons as if dancing in the moonlight, while the third is a triumphant horn-driven climax.

Tweedy’s confessional lyrics leap out early on, with the album’s second song, “She’s a Jar.” While it initially feels tender, the song reveals a dark underbelly, particularly in its hushed final moments: “She begs me not to hit her.” It mirrors the red-eyed, intentional (and in retrospect, probably problematic) cruelty of Foxtrot’s “I Am Trying To Break Your Heart.” Both songs find Tweedy slipping into character, a nastier version of himself who can transform from moderately upset to enraged without warning. That same ugliness permeates “Via Chicago,” where Tweedy casually muses, “I dreamed about killing you again last night but it felt alright to me.” At its core, the song is simple, but its construction feels precarious, as if it might teeter into chaos. “ELT” splits the difference, melding a dour message (“Every little thing’s gonna tear you apart”) with an exuberant, radio-ready melody.

But the album never feels punishing; its grimmest moments are counterbalanced with glistening, kaleidoscopic pop. Sequenced immediately after the wounded “We’re Just Friends” is “I’m Always In Love,” with its chugging rhythm, squealing synths, and instantly likeable hook. “In a Future Age”’s heavy philosophical ruminations are sandwiched between the shimmering title track and the Elvis Costello-esque “Candyfloss.” Tweedy chants the titular mantra of the buoyant “Nothing’severgonnastandinmyway(again)” like a self-help exercise, as if he can make it true by sheer force of will.

Summerteeth is a flawed album, one that wobbles a bit under the weight of its length (almost exactly an hour) and would likely benefit from a leaner tracklist. “My Darling,” a swaying lullaby that reads like a dedication to Tweedy’s son, Spencer, bears good intentions but never rises above a series of whispery platitudes (he doesn’t want him to grow up too fast, and also, he would like the good times to last). “How To Fight Loneliness” stumbles into unapologetic melodrama, and as strong as “A Shot In the Arm” is, no one could credibly argue that its remix, redundantly placed later on in the album’s tracklist, is essential listening.

But the record’s flaws are secondary to its achievements. With their eagerness to shred the playbook with each album, Wilco developed a reputation as “America’s Radiohead” in the early 00s that they upheld for most of the decade; much as that banned shunned the soaring guitar rock of The Bends and OK Computer for the steely electronics of Kid A, Wilco evolved seamlessly from, say, the aloof frostiness of A Ghost Is Born to 2007’s warm, domesticated Sky Blue Sky. That tendency toward reinvention started here. As the years have passed, these inclinations have softened; Wilco’s last few albums, pleasant though they are, never feel particularly ambitious, eschewing Tweedy’s affinity for grand statements and dramatic reinventions.

That early pivot, though—that willingness to venture into uncharted territory—is what makes Wilco a transcendent band rather than merely an admirable one. Examples of that sort of adventurousness are all over Summerteeth, and they would inform everything that came after. You can draw a direct line from Summerteeth’s Mr. Rogers-y sweater vest of a song “When You Wake Up Feeling Old” to the suburbanized balladry of Sky Blue Sky. “Via Chicago”’s spiral into a squall of shrieking, discordant guitar foreshadows the chaos of Foxtrot’s dizzying climactic moment, “Poor Places.” And if you peel back a layer of studio indulgence, almost everything here could be a precursor to the streamlined, digestible folk rock of 2009’s Wilco (The Album).