You'd never peg Dave Kolker as a blues guitarist. After all, the prototypical bluesman's got a laid-back charisma that's at once unaffected and cocky—fedora slightly tipped on the head, cigarette ensconced between loosely pursed lips, white long-sleeve shirt worn halfway unbuttoned to reveal a chest of sweat, and glass of Dewar's sitting obediently at stage's edge.

Kolker is, if anything, the anti-rock star. Bespectacled, short, and muscular, he initially strikes you as an uncanny cross between Rick Moranis and Rivers Cuomo, though he belies the clumsy persona of the former and the lankiness of the latter. He looks as if he works for an investment bank because he does.

But then he steps onstage, introduces himself with a couple of new songs he's been working on, and suddenly all of the superficial attributes that made him so endearingly normal are swept under the rug. He is transformed into something almost, well, godlike, and you can't help but wonder how he lives this other existence sorting through numbers.

Kolker's been playing the guitar since he was five, and his fingers—used to pushing his glasses in place—know every inch of the instrument, moving preternaturally over the late-'50s Stratocaster he often plays with. His mind-blowing solos—perhaps the definitive demonstration of his virtuosity—find him possessed by something remarkable.

Lucky for him—and for us—he's got equally remarkable musicians by his side: saxophonist Isamu Sato, a slender, diminutive man who manages to take hurried drags of his cigarette before taking his turn in the spotlight; Tim Luntzel, who resigns himself to facial gestures that follow the jumping backbeats of his bass; relative newbie drummer Tony Mason; and Paul LeFebvre, undeniably the most reserved of the group, who sets the imperative tone of each song with his lap steel guitar.

Kolker and his band have been playing every Tuesday at the Baggot for three years (barring two missed days, one for Kolker's honeymoon and the other on 9-11). In that time, they've crafted a winning mixture of straight-ahead rock and blues—a sound that eschews the rigidity of either genre, and consequently bends the unlikeliest ears.

But it's Kolker's markedly individualistic style that is behind that sound. He has an ability to manipulate the most subtle ramblings. The result is alternately moody, sensual, and, at times, aggressive. You never get more than a hint of this on Kolker's releases, including the new Letting Go, as the Kolker you hear recorded isn't nearly as dynamic and unrestrained as the Kolker onstage.

As a songwriter, Kolker's lyrics are nothing extraordinary, though not altogether inconsequential. They're simple (at times to a fault), concrete, and usually about (what else?) love and heartache. He sings them in a Clapton-tinged style that, while lacking the range of some of his brethren, suits the temper of his songs just fine. And besides, his guitar often does the singing for him.