If there"s such a thing as narrow-focus versatility, this set"s a prime example. Duke Robillard has cut jazz, swing, rock, and instrumental albums, and he was Tom Waits"s 2006 tour guitarist. Now the virtuoso returns to his true love--the music that first brought him acclaim as founder of Roomful of Blues--with two CDs that explore all aspects of the style. Dirty Chicago grinds like "You"re Killin" Me Baby" tumble into gentle swingers like Robillard"s take on T-Bone Walker"s "Treat Me So Lowdown" and the hushed Wes Montgomery-influenced "Stoned." He conjures a raw Mississippi-juke-joint sound to interpret "Everything Is Broken," a tune penned by another former employer, Bob Dylan. And electric and acoustic guitars, plus some lute-like sax, are used to magnify the hoodoo vibe of Waits"s "Low Side of the Road." Robillard also experiments with his voice, dropping to his lowest register to echo Bo Diddley"s brawny growl as he covers the rock godfather"s "Who Do You Love." These 23 numbers culminate with "Stretchin"," a nine-minute guitar-and-organ showcase that evokes the soul-jazz style invented by Jimmy Smith, concluding a "World" tour that"ll please blues guitar lovers. --Ted Drozdowski