For the A Ghost Is Born recording, Wilco was Jeff Tweedy, John Stirratt, Leroy Bach, Glenn Kotche, and Mikael Jorgensen; Jim O'Rourke, who mixed the band's previous release Yankee Hotel Foxtrot, co-produced the album with Wilco. Leroy Bach left Wilco at the completion of the sessions and the band announced the addition of two new members: Pat Sansone and Nels Cline. Sansone and Cline toured with Wilco to promote AGIB and that lineup has remained unchanged since 2004. As Tweedy said to Mehr for his new liner note, "Making that record, and then finding this lineup, that was the start of something-of having a band that can play anything. That's why, twenty years later, we're still here and still going. "Wilco first began sessions for what would become A Ghost Is Born in early 2002 at Chicago's Soma E. M. S., where they had mixed Yankee Hotel Foxtrot. Much of the album was tracked live in the studio with O'Rourke and engineer Chris Shaw.
They also reunited there with engineer and soon-to-be-bandmate Mikael Jorgensen. At Soma, the band began sketching out music using Tweedy's notebooks of lyrics, poetry, and prose. Mehr notes: "In between more traditional song tracking, the group would engage in a series of conceptual improvisations in the studio. These musical experiments, broadly known as 'Fundamentals'... were part of what Kotche said was 'an attempt to search for a new group identity. To see what we could make this band into. '"In the fall of 2003, the band relocated to New York to finish recording at Sear Sound. "It seemed like the band needed to get out of Chicago, get out of the working mode they'd been in, and only be thinking about making a record," O'Rourke told Mehr. There, playing together in the corner of a large studio, the album began to take it's final shape. Emerging from a period of addiction and rehab, Tweedy discussed how he feels about A Ghost Is Born in retrospect. As he told Mehr, "I was worried the album was going to feel like something dark and not me anymore. But the album was ahead of me as a person. It was the part of me that I was trying to preserve-enthusiastic and furious about the world, as well as open and loving. I reached that in the music, before I could get there emotionally on my own. "
