If there were ever an artist who won on points for ambition, Beth Patterson's the one. She sings lead vocals and, on her recordings, backup too. She plays an arm's-length list of instruments. She writes her own songs, and she does fantasy artwork for her albums, one drawing for each song. Some of her music deals with cosmic, metaphysical themes, and she's beautiful, to say the least. One of her albums has an epigraph from Goethe. She sings in English, Gaelic, and on occasion the Cajun French of her native Lafayette, Louisiana. Sometimes her lyrics are tough going, but often enough she hits the spot with a line that hangs in your head: "It was a cobra-mongoose war of wills" and "We meet ourselves with doglike devotion / Catch fleeting tail in the mouth of emotion."

At the center of Patterson's sound is the Irish bouzouki, which she plays in eight- and ten-string versions. The bouzouki, which the Irish revivalists of the 1960s picked up from Greek rebetika music and made their own, serves Patterson as a similar stylistic hinge: it becomes the basis for a big sound that's Celtic in flavor but not in detail and allows for excursions into other styles. Patterson is at her best when she matches Irish dance rhythms to her own distinctive lyrics in an original way.

Patterson's three albums on her own Little Blue Men label differ sharply from one another, and one reason to see her show might be to experience a young artist at that heady stage of blazing through new territory. Her debut, Hybrid Vigor, was a Celtic fusion affair that ventured into swing, Louisiana music, and more. Take Some Fire was a lyrically ambitious work with a full band and lots of rock influences. Patterson's recent live album, Caught in the Act, features just the artist and her bouzouki. If her July Ark show follows the pattern of the music on that CD, expect a move in the direction of Irish traditional music and a delightful sense of humor attuned to the tastes of the folk and coffeehouse audiences Patterson has been pursuing. Singing traditional songs has made Patterson bear down and hone an edge on her voice that wasn't there before.

Only the highly adventurous among the Celtic crowd are going to like Beth Patterson; it's not so much the stylistic diversity that will discourage the others as the total individualism of her music in a genre with a communitarian ethos. And she's way too low tech at this point for pop success. Which leaves those of us who love those all-American musicians who swing for the fences.

Beth Patterson comes to the Ark on Tuesday, July 5.