"She's beautiful," writes Irish-American art historian Patricia Dolan in the first of the journal entries that form The Music Lesson. "I look at my face in the mirror and it seems far away, less real than hers."   The woman she describes is the subject of the stolen Vermeer of the novel's title. Patricia is alone with this exquisite painting in a remote Irish cottage by the sea. How she arrived in such an unlikely circumstance is one part of the story Patricia tells us: about her father, a policeman who raised her to believe deeply in the cause of a united Ireland; the art history career that has sustained her since the numbing loss of her daughter; and the arrival of Mickey O'Driscoll, her dangerously charming, young Irish cousin, which has led to her involvement in this high-stakes crime.          How her sublime vigil becomes a tale of loss, regret, and transformation is the rest of her story. The silent woman in the priceless painting becomes, for Patricia, a tabula rasa, a presence that at different moments seems to judge, to approve, or to offer wisdom. As Patricia immerses herself in the turbulent passions of her Irish heritage and ponders her aesthetic fidelity to the serene and understated pleasures of Dutch art, she discovers, in her silent communion, a growing awareness of all that has been hidden beneath the surface of her own life. And she discovers that she possesses the knowledge of what she must do to preserve the things she values most.