A great open secret of the last act of Buddy Guy's career is that nearly every album he's made in the new millennium is a concept album of sorts, ranging from the gnarled modern Delta blues of Sweet Tea and the acoustic Blues Singer to the pseudo-autobiography of 2010's Living Proof.

Rhythm & Blues trumps them all in size and concept: it's a double-disc set divided into one disc of "Rhythm" (aka soul) and one disc of "Blues" (aka blues of the Chicago variety).

Several stars come out to help Guy along, top-lined by three-fifths of Aerosmith on "Evil Twin" and Kid Rock on, naturally, "Messin' with the Kid." The former arrives on "Blues" and the latter on "Rhythm," which suggests how fluid the lines are between the two discs.

But it's also generally true that the "Rhythm" disc is big, bold, and brassy in a way Buddy rarely is; often, it's much closer to the late, great Bobby "Blue" Bland, albeit a hyper-charged, over-scaled version of soul-blues.

Guy has rarely attempted this kind of horn-driven, soulful blues and it's fun to hear him tackle such sounds as he wrestles the rhythms while spitting out gonzo, gnarly guitar runs.

Better still, he finds a place to settle down within the slinky grooves of "I Go By Feel" and the Keith Urban duet "One Day Away," which are not only the two greatest surprises in tone, but also the two songs that sink their hooks in deep.

That's not always the case here, at least for the originals, particularly on the "Blues" disc which either trades in pastiche ("Meet Me in Chicago," "All That Makes Me Happy Is the Blues") or function as simple showcases for Guy's guitar.

If this package can sometimes feel a little too pat, put the blame on producer Tom Hambridge, who also helmed Skin Deep and Living Proof and now has a track record of pushing Guy just enough to form a narrative but not enough to break him out of the box.

Buddy himself remains a bit of a live wire, his voice sounding younger than Steven Tyler's and his guitar continuing to be a muscled monster that steamrollers everything surrounding it.

That continued potency is reason enough to give Rhythm & Blues a spin.