By Richard Dyer

Lorraine Hunt Lieberson is authentic, and that's why audiences respond to her. To the glowing ruby of her voice, she adds intelligence, musicianship, technique, stage presence, and an inner fire. Business-as-usual is just not worth her time; she prefers to work with music she finds challenging and people she finds sympathetic. She's a good colleague, but a dangerous person to be with onstage if you don't have comparable concentration, conviction, and charisma. Her voice compels you to listen as intently as she sings, and you can't take your eyes off of her.

For a long time, Musical America's Vocalist of the Year wasn't even sure she wanted to be a singer. Lorraine Hunt Lieberson did appear in her California high school production of Fiddler on the Roof, but she had also been studying viola. Although she began the opera program at San Jose State, she didn't enjoy the competitive atmosphere and decided to concentrate on viola. She loved being an inner voice, says Lieberson. The viola took her to the Tanglewood Music Center, and then to Boston, where she soon became active on the freelance circuit, particularly in new music. The first time I heard her, she was performing Leon Kirchner's Third String Quartet-the result of more than 50 hours of rehearsal. During her viola years, Lieberson quietly resumed vocal study at the Boston Conservatory.

Her first years as a singer were experimental; some of the vocal firebombs she threw exploded in her face. But she's never lost her sense of daring and delight in risk-taking. She does feel she wasted too much time trying to be a soprano, forcing her voice to fit into an uncomfortable category: "I don't like labels," she said, "if I don't have to have one. I just want to sing what I can sing." Slowly her voice found its center of gravity in an enviably luscious viola register-she sings with a precision of tuning that suggests a great string player.

Her first operatic role was Hansel in Hansel and Gretel, and she sang it in San Quentin Prison, of all places. Her friend Kent Nagano, then a young and unknown conductor, coaxed her into participating in a prison tour-even then her acting must have been convincing, because one of the prisoners was astounded to see her leaving as a young woman. "I thought you were a boy with a broad behind," he called out.

She also auditioned for Craig Smith, director of Boston's Emmanuel Music. In the summer of 1984, Smith chose her to sing Tamiri in a concert performance of Mozart's Il rè pastore at the Castle Hill Festival, the beginning of her career as a professional singer. The next summer brought Handel's Giulio Cesare with Smith and Peter Sellars at the Pepsico Summerfare festival in Purchase, New York. Lieberson's tormented Sesto, sung with coiled-serpent concentration, put her on the map. I remember introducing her to New Yorker critic Andrew Porter in the lobby and feeling only a little surprised when he said, "It's a pleasure to meet America's greatest singer."

Lieberson's unpretentious platform manner is a mirror of her offstage personality. One of my favorite memories dates back to the late 1980s, when Sellars, in the first flush of celebrity, appeared as the villain in an episode of Miami Vice. His mother, Patricia, decided to give a Miami Vice party so everyone could watch the show. As I made my way up the street, Lieberson emerged from a taxi dressed in a vinyl miniskirt as a Miami hooker. She stopped traffic.

Her first recording was with Seiji Ozawa and the Boston Symphony, who called her at the last minute to sing the beautiful chanson that is usually omitted from Fauré's incidental music for Pelléas et Mélisande. Her recordings with the Philharmonia Baroque under Nicolas McGegan (Susanna, Theodora, and Messiah) brought her work to an international audience, and to the attention of William Christie, who chose her for performances of Charpentier's Médée and Rameau's Hippolyte et Aricie. Her performances observed the conventions of period performance but also communicated the kind of emotional intensity that finally made you understand those accounts of 18th-century operagoers swooning away from the onrush of uncontrollable emotions. As a recitalist, she looks the audience in the eye and sings directly to them with absolute and sometimes unnerving candor. A BBC CD of a 1998 recital recorded live in the Wigmore Hall gives some idea of her unique qualities, particularly the glow of her performance of Mahler's Rückert Songs.

That disc was her first as Lorraine Hunt Lieberson. In 1997, she sang in the premiere of Peter Lieberson's opera Ashoka's Dream in Santa Fe, and a year later she married the composer. He has written his subsequent vocal music with his wife's voice and temperament in mind, and she never fails to include a group of pieces by her husband on her recital programs.

Lorraine Hunt Lieberson has always been strongly drawn to new music. She has participated in workshop productions of Robert Aldrich's opera Elmer Gantry and in the first performance of John Harbison's Pulitzer Prize-winning The Flight into Egypt; later she premiered and recorded Harbison's Due Libri di Montale. Her schedule late in 2000 took her to Paris to appear under Peter Sellars's direction in the premiere of John Adams's El Niño, conducted by Kent Nagano.

Lieberson continues to go her own way. Her opera fans probably wish she wouldn't sing so much new music; her friends in the new-music community are grateful for her advocacy but wish she had more time to spend with them. Her management regrets that she can say "no" with such ease. She tried out her Carmen with the Boston Lyric Opera, and some people found her the most compelling contemporary performer of the role, but she hasn't done it again because the right set of circumstances hasn't yet presented itself.

Last season she finally made her Met debut as Myrtle in the premiere of Harbison's The Great Gatsby. Myrtle appears in only two scenes, but Lieberson dominated the opera. Harbison tailored the bluesy music to her voice, and Lieberson understood that Myrtle feels immortal longings, just like Gatsby.

Lieberson is generous in sharing her emotional experience when she sings. She knows that to sing meaningfully she has to have something to sing about. Once she cleared an entire season to take care of her sister while she struggled with cancer; it is important for her to spend time with her husband in Santa Fe, looking at the mountains and feeling the light. Lieberson is a great singer because she knows what she is singing about, and where she is singing from. Singing, like playing an inner voice in a string quartet, connects her to her inner life.

Richard Dyer is the music critic for The Boston Globe.