Mermaid Avenue Vol. II is patchier but no less enjoyable than its predecessor. The album is less folky, as most of the album's highpoints are more rooted in rock 'n' roll than folk, such as "Airline to Heaven" with its tantalizing drum rhythms and chorus, the rollicking and downright fun "Feed of Man" with its joyous guitar licks, or "Blood of the Lamb," an eerie mix of thumping drums and bells that would not sound out of place on Bob Dylan's recent Time Out of Mind.

These sounds do not appear on Vol. I, and the result is stunningly good. The diversity of this album is even more startling than on its predecessor. Not only does every song sound different from previous tracks, each song belongs to a different genre. Beyond the album's rock tunes are some delightfully dirty blues tracks like "All You Fascists" and "Meanest Man," which would fit perfectly on the next Tom Waits record. Bragg even touches on some jazzy drum shuffling and vocals on the very slick "Stetson Kennedy."

However, Wilco and Billy Bragg do not ignore the folk roots that pervaded Vol. I. "I was Born" is straight from the vein of that album's "Ingrid Bergman," and most will recognize "Eisler on the Go" lurking beneath the surface of the gorgeous acoustic ballad, "Black Wind Blowing."

Yes, this album does stretch the listener's attention span a bit more. The music is indeed more challenging, but delicately so. It is difficult to imagine that this talented group could deliver an album of as much meat as Vol. I, but they have, proving that the union of Wilco and Billy Bragg just might be one of the most outstanding musical projects in modern folk-rock history. But let's not forget that these Mermaid Avenue albums are only made possible by the brilliant songwriting legacy of one named Woody Guthrie.