By JON PARELES

Even without hearing Sonny Landreth's slide guitar, watching his hands would show a virtuoso at work. When he led his trio at the B. B. King Blues Club on Tuesday night, Mr. Landreth plucked notes with his thumb, fingers and a pick, or tickled the strings with a wiggling finger. He hit the strings with a closed fist and stroked them with an open palm. He strummed with choppy strokes, clawed the strings or let his hand hover in a trembling blur.

That was just his right hand: his left was forming notes with slide and fingers, swooping up and down the neck, tapping precise notes or grabbing and bending them. And the sounds were even better than the view.

Mr. Landreth and his band members, Dave Ranson on bass and Kenneth Blevins on drums, come from the bayou country around Lafayette, La., although they have covered a lot of mileage both on their own and as John Hiatt's backup band, the Goners. Mr. Landreth writes songs with bar-band titles like "Blues Attack" and "Pedal to Metal," and they are still Louisiana bar-band music.

They are rooted in blues, zydeco, New Orleans mambo and the Celtic modes of Acadian music; Mr. Landreth sings in a swamp-rock moan about a two-timing lover or trailer park called the Promised Land, with pain, humor and rowdiness. The band's shuffles and boogies would have been dance music if the club had a dance floor. No doubt they are in Lafayette, where Mr. Landreth recorded much of the same set for a blistering new live album, "Grant Street" (Sugar Hill).

With Mr. Landreth's guitar at their center, the songs carry bar-band music to a higher evolutionary plane. He knows all the old methods of the slide-guitar blues: the lunging chords, the dialogues of low plunks and high keening notes, the wailing, wriggling, vocalistic long lines. But he has another tier of techniques as well. There are chords that chime, dance atop the beat, mutate in midair or huff like a harmonica. There are fast-picked overtones that arrive like a tuned hailstorm and gutsy nuances of distortion and feedback. The effects can be startling, but they're never gratuitous. They are the sounds of a musician who has deeply investigated his instrument without leaving his roots.

Mr. Landreth was topping a slide-guitar triple bill. It also included the Campbell Brothers, a gospel group from a church tradition, known as sacred steel, that makes a joyful noise with slide guitars. Bob Brozman, opening the concert, calls himself a "guitar anthropologist." He went hop-scotching across the world map with impressive technique, but his hyperactive pacing sacrificed songs to effects.