It's easy to think of the Black Keys as the flip side of the White Stripes. They both hail from the Midwest, they both work a similar garage blues ground and both have color-coded names. If they're not quite kissing cousins, they're certainly kindred spirits, and they're following surprisingly similar career arcs, asthe Keys' third album, Rubber Factory, is neatly analogous to the Stripes' third album breakthrough,White Blood Cells. Rubber Factory finds the duo expanding, stretching, and improving, coming into its own as a distinctive, original, thoroughly great rock & roll band. With 2003's Thickfreakness, guitarist/vocalist Dan Auerbach and drummer/producer Patrick Carney delivered on the promise of a raw, exciting debut by sharpening their sound and strengthening the songwriting, thereby upping the ante for their next record, and Rubber Factory doesn't disappoint. Instead, it surprises in a number of delightful ways, redefining the duo without losing the essence of the band. For instance, the production has more shades than either The Big Come Up or Thickfreakness -- witness the creepy late-night vibe of the opening "When the Lights Go Out" or how the spare, heartbroken, and slide guitar-laden "The Lengths" sounds like it's been rusted over -- but it's also harder, nastier, and uglier than those albums, piled with truly brutal, gut-level guitar. Yet through these sheets of noise, vulnerability pokes through, not just on "The Lengths," but in a lazy, loping, terrific version of the Kinks' "Act Nice and Gentle." And, like their cover of the Beatles' "She Said, She Said" on their debut, "Act Nice and Gentle" illustrates that even if the Black Keys have more legit blues credentials than any of their peers, they're nevertheless an indie rock band raised with not just a knowledge of classic rock, but with excellent taste and, most importantly, an instinct for what makes great rock & roll. They know that sound matters, not just how a band plays but how a band is recorded, and that blues sounds better when it's unvarnished, which is why each of their records feels more like a real blues album than anything cut since the '60s. But they're not revivalists, either. They've absorbed the language of classic rock and the sensibility of indie rock -- they're turning familiar sounds into something nervy and fresh, music that builds on the past yet lives fearlessly in the moment. On a sheer gut level, they're intoxicating and that alone would be enough to makeRubber Factory a strong listen, but what makes it transcendent is that Auerbach has developed into such a fine songwriter. His songs have enough melodic and lyrical twists to make it seem like he's breaking rules, but his trick is that he's doing this within traditional blues-rock structures. He's not just reinvigorating a familiar form, he's doing it without a lick of pretension; it never seems as if the songs were written, but that they've always existed and have just been discovered, which is true of any great blues song. Carney gives these songs the production they deserve -- some tunes are dense and heavy with guitars, others are spacious and haunting -- and the result is the most exciting and best rock & roll record of 2004.