Back in 2002, it seemed easy to discern which of the Midwestern minimalist blues-rock duos was which:the White Stripes were the art-punks, naming albums after Dutch art movements, while the Black Keyswere the nasty primitives, bashing out thrilling, raw records like their 2002 debut The Big Come Up and its 2003 follow-up Thickfreakness. Six years later, the duos appear to have switched camps, as Jack White leads the Stripes down a path of obstinate traditionalism while the Black Keys get out, way out, on their fifth album, Attack & Release. Evidently, their 2004 mini-masterpiece Rubber Factory represented the crest of their brutal blues wave, as ever since singer/guitarist Dan Auerbach and drummer Patrick Carney have receded from the gnarled precision of their writing and the big, brutal blues thump, they started to float into the atmosphere with their 2006 EP-length tribute to Junior Kimbrough, Chulahoma. Ever since then, the Black Keys have emphasized waves of sound over either ballast or song, something that should be evident from the choice of Danger Mouse as the producer of Attack & Release, a seemingly unlikely pair that found common ground in the form of Ike Turner. Danger Mouse worked with the rock & roll renegade when he produced the Gorillaz's Demon Days and the plan was to have the Black Keyscut an album with Ike but Turner's death turned the project into a full-fledged Keys album. That's the official story, anyway, but the timeline doesn't quite seem to fit -- Ike died December 12, 2007 and a finished copy of Attack & Release was out in February, which is an awfully short turnaround to complete an album -- nor does the sound of the album seem to fit that timeline, either, as it's elliptical, open-ended, and reliant on the spacy sonics the Black Keys have sketched out since Rubber Factory, so it's hard to imagine where Turner would have fit into this. But it's not hard at all to see how avant guitarist Marc Ribot fits into this elastic mix, as this is the kind of restless, textural roots-aware rock reminiscent of the spirit, if not quite the sound, of Elvis Costello and Tom Waits, two mavericks Ribot has played with in years past. This shift to sound over song has been so gradual for the Black Keys that Ribot's cameo doesn't seem intrusive, nor does Danger Mouse's hazy production feel forced upon the band, it's filled with details so sly they're almost imperceptible. As always, Danger Mouse encourages the band to intensify what's already there, and so Attack & Release willfully drifts, as dreamy, artfully sonic sculptures are punctured by Auerbach's rumbling guitars and Carney's clattering drums. But where the interplay of the Auerbach and Carney always felt immediate in their earliest work, there's a bit of a remove here, with the riffs used as paint brushes instead of blunt objects. The same can be said of the songs, where even the most immediate tunes -- "Psychotic Girl," the B-side "Remember When" -- don't grab and hold like those on the group's earliest records, and they're not really growers either, as the point here is not the individual tunes but rather the greater picture, as everything here weaves together to create a mood: one that shifts but doesn't stray, one that's nebulous but not formless, one that's evocative but not haunting. To be sure, it's an accomplishment and one that showcases the Black Keys' deepening skills but at times it's hard not to miss how the duo used to grab a listener by the neck and not let go.