Fall Out Boy walked into Ocean Studios in Burbank in November 2004 with a clean division of labor they had never fully formalized before. Patrick Stump would write every note of music. Pete Wentz would write every word. That split, applied across an entire album for the first time on what would become From Under the Cork Tree, is the reason the record hit the way it did. The hooks were pure Stump, melodically generous and radio-ready. The words were pure Wentz, anxious and raw and occasionally desperate. Put them together and you got something that neither could have built alone.

The path to Ocean Studios was stranger than it looked from the outside. Fall Out Boy had released Take This to Your Grave on Fueled by Ramen in May 2003, funded by an Island Records advance that came with a right of first refusal on their next record. They toured relentlessly, building a fanbase through MySpace and an endless van circuit. By the time they returned to the studio in November 2004, they were carrying the full weight of a major-label debut. The Stump-Wentz split had existed in partial form on Take This to Your Grave, applied to some songs but not all. Cork Tree was where it became the rule.

Producer Neal Avron, who had worked with New Found Glory and The Wallflowers before Fall Out Boy came calling, ran two weeks of pre-production: one week in Chicago, one week in Los Angeles. Avron's instinct was structural. He heard Wentz's rough demos and recognized that "Sugar, We're Goin Down" and "Dance, Dance" were great songs underneath the noise, and he built the sessions around getting that greatness onto tape. Stump was the one in the room with him, working out arrangements and sounds. Wentz was the vision and the words. The mixing credits on the finished album reflect how much was at stake: Avron mixed the majority of tracks himself, and Tom Lord-Alge, one of the most in-demand mixers in rock, handled "Of All the Gin Joints in All the World," "Dance, Dance," "Sugar, We're Goin Down," "Sophomore Slump or Comeback of the Year," and "A Little Less Sixteen Candles, a Little More 'Touch Me'." That is a label betting on singles.

The sessions broke apart in February 2005 when Wentz, living in Los Angeles with the rest of the band, attempted suicide by overdosing on the anxiety medication Ativan. The record was paused. Wentz sought help, spent time recovering, and rejoined the band before the album's May 3 release. What matters, musically, is that the darkness Wentz was writing through was already embedded in the tracks. "7 Minutes in Heaven (Atavan Halen)," which features Brendon Urie of Panic! at the Disco on vocals, takes its title directly from the medication Wentz overdosed on, and the song moves through sedation and encroaching numbness like a document of the period. "Get Busy Living or Get Busy Dying (Do Your Part to Save the Scene and Stop Going to Shows)" builds from a brooding mid-tempo verse into something that sounds like a person arguing themselves back into existence. Wentz described the album's lyrical themes as being about "the anxiety and depression that goes along with looking at your own life." That is a confession embedded in a pop-punk record that went on to sell over seven million copies worldwide.

The guest credits on the album are a small scene document. Brendon Urie appears on "7 Minutes in Heaven," William Beckett of The Academy Is... sings on "Sophomore Slump or Comeback of the Year," and New Found Glory contribute vocals to track ten, "I Slept with Someone in Fall Out Boy and All I Got Was This Stupid Song Written About Me." These were friends from the same circuit, the same Warped Tour vans, the same internet-forum fanbase ecosystem that had kept all of them alive before radio touched any of them. The album's lead single, "Sugar, We're Goin Down," entered the then-still-powerful MTV show Total Request Live driven by fan votes. The band played Warped Tour that summer. By fall, "Dance, Dance" was the second single. The album debuted at No. 9 on the US Billboard 200. By the time the Grammy nomination for Best New Artist arrived in early 2006, the thing was already irreversible.

What the Stump-Wentz split produced was a record where the feelings were genuinely Wentz's and the music was genuinely Stump's. Neither one could soften the other's contribution into something comfortable. The lyrics were too specific and too personal to be mistaken for genre convention. The melodies were too good to be dismissed as background noise for the words. From Under the Cork Tree landed in May 2005 as a pop-punk album, but what it actually was, was two people finding out what they could build when they stopped sharing the controls.