Wilco's follow-up to A.M. impresses first with its size: 19 tunes fill the double-CD package, and the packaging unfolds like a larger-than-life 1970s-era gatefold album cover. But the love affair with the artwork is short-lived, fading as the music takes center stage, making plain the band's overwhelming stretch into innumerable styles. Jeff Tweedy's love of pop and the mechanics of making pop albums is clear almost immediately, as he and his cohort utilize the studio to create and manipulate undertows and snaky recorded elements throughout many of their tunes (a keyboard touch, a guitar's flair, a cymbal's unexpected crash). There are the plainspoken acoustic numbers, recalling Tweedy's tenure in Uncle Tupelo, and there are also unwinding swoops of tinted, guitar-heavy rock--one of which collapses into chromatic jabs at a piano only to resolve in silence on "Sunken Treasure." Oodles of influences fill Wilco's collective mind, and they're perfectly content to pile the trace elements atop each other and make scrambled pop perfection. --Andrew Bartlett