Following the 1994 breakup of alt country pioneers Uncle Tupelo, co-founder Jeff Tweedy immediately formed Wilco. Over the next three albums, the band recorded the rootsy A.M., veered toward the orchestral pop of Being There, and earned a Grammy nomination for Mermaid Avenue (an album of Woody Guthrie lyrics for which the band and Billy Bragg wrote music), before running toward a sunny, West Coast-inspired pop utopia of complex introspection with Summer Teeth. Upon parting ways with founding member Jay Bennett, Wilco independently released (after some wrangling with Warner Bros.) Yankee Hotel Foxtrot. It was with Foxtrot that Wilco succeeded at leaving any alt country vestiges behind, venturing into more moody, dislocated songwriting tangled up inside noise experiments and amputated guitar leads. Wilco's fifth album A Ghost Is Born continued to help the band search for their sound somewhere between sonic gambles and innovative production. Their sixth, Sky Blue Sky, came in the spring of 2007, sounding like a return to simplified guitar pop with sing-along songs that unfold and unleash stormy guitar solos courtesy of Nels Cline. Some songs even hint at a slight return to the band's twangy roots.