If you take Aguilera's idea of the 2-CD set at face value, Back To Basics is the singer's tribute to pre-WWII-era jazz. Not so much. The Linda Perry-produced second half of Back To Basics comes off as an MTV reimagining of the 20s-40s as seen in movie musicals. Welcome is Cirque de Soleil meets Cabaret meets 4 Non Blondes, and the Betty Boop booty sass of Candyman finds Aguilera cooing anachronistic come-ons over Technicolor horns, though I Got Trouble is a passable stab at bootlegger blues. On its own, Disc 2 would be risky enough for a mainstream pop diva, but the Mark Ronson- and DJ Premier-assisted first half of the project likely has Sony BMG execs sighing in relief. Primo indulges Xtina's retro fetish with Jazzmatazz-y scratchy samples and raunchy 60s R&B loops, but it's wholly a contemporary soul-pop assault, with one killer track (lead single Ain't No Other Man), some standout floor-fillers, decent ballads and one gross misstep in fan-fellating (Thank You). And ultimately, Aguilera's the only one of her peers with the vocal prowess to pull it off.