It is an oddity of our culture that more people own David McCullough's book John Adams than any CD of music by the most prominent composer today, also named John Adams. Twenty years ago Adams seemed poised to lead contemporary art music out of the wilderness. Since that time his large body of work has bolstered Adams's position as the most influential, technically gifted, and aesthetically ambitious composer of his generation. The vibrant rhythms and dazzling orchestration of The Chairman Dances (1985) and Short Ride in a Fast Machine (1986) have made them orchestral staples, yet his music is less familiar to the public than the work of George Gershwin, Aaron Copland, or Leonard Bernstein. Even though many composers now cultivate an audience-friendly style, new "serious" music remains nearly as marginal as it was during the heyday of academic atonality.

Adams's symphonic works, which at times sound like Sibelius superimposed on a Eurorock rhythm track, and his two controversial operas, Nixon in China (1985) and The Death of Klinghoffer (1990), mirror our confused feelings about the function of art music. Indeed, they revel in our ambivalence. But his recent On the Transmigration of Souls is a breakthrough. Terrifying and heartrending, it offers reassuring proof that contemporary classical music—too often dismissed out of hand as obscure and unpleasant—has something unique to say to a wide public.

Composers today can get tripped up by contrary expectations. They are told to be mavericks in the hopes that quirkiness will lure bright young listeners from alternative rock. But they are also told to make their music accessible and romantic, in order to reach—or at least not repel—the traditional (and older) concertgoer. What sets Adams apart, even more than his technical flair, is his ability to heed these mixed signals with a Whitmanesque desire to embrace contradictions. Adams's music contains multitudes of ideas and moods. It is by turns goofy and grave, spiritual and erotic (sometimes both at once), extravagant and severe, profound and sophomoric. No contemporary music can compete with his for sheer beauty of sound—or, at times, for the power to offend listeners.

Adams will be almost unavoidable this year. He has major premieres in Los Angeles and San Francisco, and is the focus of a festival presented by the Great Performers series at Lincoln Center. I can think of no living composer, and few artists in other media, whose work is more informed by the pleasures and terrors, hopes and disenchantments, of contemporary life. His music makes complex ideas vibrate with troubling energy. And like the greatest music of the past—Bach, Beethoven, Mahler—it can take us beyond those troubles and complexities to states of serenity, wisdom, and peace.

Adams, now fifty-six, grew up in New England, and while a student at Harvard he played clarinet in the Boston Symphony. After college he went to San Francisco, where he joined the anti-academic scene of minimalists, including Terry Riley (who launched the movement in 1964 with his ecstatically repetitive and tonal In C), and Pacific Rim composers, including Lou Harrison, who while atonal angst ruled on the East Coast continued to write euphonious, tonal music. In the late 1970s Adams found a way to synthesize the styles of the two coasts, and his music has defied critical pigeonholing ever since. Works such as Phrygian Gates (1977), Shaker Loops (1978), Harmonium (1980), and Grand Pianola Music (1982) brought minimalism out of the lofts and into the concert hall. He infused a countercultural style with traditional musical ideas it had previously resisted, recasting the repetitious rhythms and simple harmonies of minimalism as virtuoso vehicles for classical performers. Adams had little use for the conceptual rigor or the emotional coolness of earlier minimalism. In the music of Philip Glass or Steve Reich everything you are going to hear appears in the first few seconds of a piece. The pleasure comes from observing the barely noticeable process of changes to the initial statement. With Adams anything could happen—and did, explosively. His post-minimalism was romantically transcendental, like the music of Liszt.

Adams also gave the symphony orchestra, that nineteenth-century artifact, a twenty-first-century sound. Harmonium, a sprawling symphony for chorus and large orchestra, demonstrated Adams's command of orchestral alchemy. By superimposing layers of instrumental oscillations and pulses Adams made the orchestra shimmer in a way not achieved since Ravel. But the symphony gave the orchestra a metallic, post-industrial sound, far from the traditional lush impressionist palette—like going from oil paint to acrylic. The density of sound (Adams writes thousands of notes) and the emphasis on the bright upper register make the live orchestra seem electronically synthesized, as if from a THX sound system.

On the Transmigration of Souls, commissioned by the New York Philharmonic to honor the victims of the 9/11 attacks, is a turning point in Adams's work and, I hope, in American music. Adams has described the piece as "a memory space." It superimposes pre-recorded street sounds and the reading of victims' names by friends and family members, also pre-recorded, on live performances by a children's chorus, an adult chorus, and a large orchestra. This complex twenty-five-minute work takes Adams's high-tech sound into a spiritual realm.

Adams's standing made it inevitable that he would be asked to compose a large-scale, highly publicized response to 9/11. Talk about performance anxiety! The Philharmonic must have been anxious about the outcome too. A master of rhythm, texture, and color but not a melodist, Adams was unlikely to produce a simple, lyrical piece like Samuel Barber's Adagio for Strings, that perfect American elegy. More worrisome, Adams's reputation had been shadowed by the controversy over The Death of Klinghoffer, a treatment of the Achille Lauro hijacking that many critics found anti-Semitic. (The opera's Palestinians appear to be noble victims; its Jews seem to have stepped out of an episode of Seinfeld.) Soon after 9/11 the Boston Symphony decided to cancel previously scheduled performances of choruses from Klinghoffer. Given Adams's leftist, green political positions (not at all exceptional in the East Bay, where he lives), the Philharmonic may have feared that he would exploit the commission to make a musical case for al Qaeda. Adams may only have heightened such fears by telling the press that he had many conflicting opinions about 9/11. But then, didn't everyone?

It is not at all obvious how music, or any other art, should respond to catastrophe. Adams's new piece left most critics awed but uncertain of their judgments, and at a loss for words—a loss I felt as I tried to imagine from the reviews what the music was like. Some critics had trouble relating the live to the taped parts of the score; the sound-on-sound texture reminded them, negatively, of movie music. I think the work makes such a powerful impact because of, not in spite of, the "extra-musical" elements; Adams was redefining the relation of music to non-music and of the concert hall to everyday life.

Transmigration does mix sound elements in a way that is unusual in classical music (Steve Reich's Different Trains is a precedent) but commonplace in a movie theater. But film soundtracks, of course, do not also feature live performers. Only Adams could have combined these different elements with such imagination and technical skill. Like many of his earlier works, Transmigration speaks in a very contemporary idiom (Adams's pieces often begin by laying down a stylized rock groove in the percussion) that is somehow haunted by a ghost of the musical past. In his great 1984 symphony Harmonielehre, Adams channels Sibelius (Fourth Symphony, 1911) and Mahler (Tenth Symphony, also 1911) in the slow movement, whose title, "The Anfortas Wound," brings the ghost of Wagner to the table. Midway through my first hearing of his recent Naive and Sentimental Music, also a monumental symphony, I became aware that, without allusions or quotations, Adams was following the flight plan of Sibelius's Fifth.

From the archives:

"The Many Faces of Ives" (January 1997)

In Transmigration, Adams has found a new familiar spirit: Charles Ives. In New York on May 7, 1915, the day the Lusitania sank, Ives witnessed an episode of communal mourning that prefigured the response to 9/11. People waiting for the elevated train gradually began to sing along with a hurdy-gurdy playing an old hymn. Ives transformed this experience into "From Hanover Square North, at the End of a Tragic Day, the Voice of the People Again Arose"—a great and rarely performed vision of a spiritualized democracy, a community brought together by music at a time of tragedy.

Adams's Transmigration builds on Ives's vision. For this occasion Adams needed Ives's example to help depersonalize his music. His earlier work is a very up-to-date post-minimalist kind of romanticism, a deeply personal music that seeks states of ecstasy and transcendence. Like a true romantic, he often found his music in dreams, and in his own spiritual conflicts. The "memory space" of Transmigration, however, had to be public, not personal, and Ives—uniquely in the history of music—created imaginary utopian venues, usually by layering different sounds. Adams has the advantage of technology: sound engineering to balance and coordinate the musical and extra-musical elements. Technology also allows him to create a music that is at once visionary and familiar. Transmigration seems more modernistic than earlier Adams: more disjunct and nondirectional, much more dissonant. Yet, without sounding in any way like popular music—as with the bad old modern music, the work has no memorable musical theme or melody—it is more successfully populist. Its sound-over-sound texture connects it to the mass media. We know this ambiance from Ken Burns documentaries, from CNN, from rap music, from the movies. Like Ives but in an entirely new way, Adams extends our sense of music—there is music in the sound bites and the street noises, music in our own state of sensory overload.

Although the opening of the piece seems like a sound collage, Adams does not mingle noises, words, and tones randomly. He sets them in a careful, therapeutic course from the secular to the sacred, leading to a vision of redemption when the sonic chaos converges to form a vast carillon. First we hear only street sounds, as if the walls of the concert hall had been blown away. In place of Adams's usual percussive groove a taped boy's voice repeats the word "missing," a verbal heartbeat that gives the unformed sound of cars and footsteps a rhythmic undertow. The chorus (at first wordless), strings, and harps enter, playing slowly rocking lines that sound like a medieval chant. Are we in the street, a concert hall, or a cathedral? The choral syllables slowly become stammered words and phrases: "re-mem ... re-mem ... re-member," "you will ... you will ... you nev ..." Noises, words, prayers: for ten minutes the music seems to drift uncertainly and in fragments on memories of Ives's The Unanswered Question, in which a distant trumpet poses the eternal question of existence. Over undulating ripples in the woodwinds the children's chorus picks up the gentle rocking lines of the opening with new words that are at once journalism and incantation: "I see buildings, I see water." Without warning the orchestra blasts a sustained chord of anguish, announcing a move to the next level of contemplation. The music becomes simpler. The two choruses repeat the words, now in full sentences, of fathers, mothers, sisters ("The daughter says, 'He was the apple of my father's eye'"), intensifying at the lines "I wanted to dig him out. I know just where he is."

The orchestra again erupts, this time in mounting waves that lead to the long-awaited answer to the question posed by Ives: their voices transformed, transmigrated, into human chimes, the choruses sing out the words "Love" and "Light" over and over, fortissimo. Very gradually the music subsides to the sound-on-sound texture of the opening, but with a new feeling of calm. Orchestra and choruses fade out; a recorded woman's voice, in an unidentifiable accent, repeats the words "I see water and buildings." The street sounds return us to our everyday lives.

In the months that followed the catastrophe, 9/11 became a source more of civic pride than of nationalism. The heroes were policemen and firemen, not soldiers; a mayor, not a President. The names read on television and the short biographies in the Times reminded New Yorkers of their diversity and their commonality. In Transmigration, Adams breaks down the divide between the high-bourgeois culture that created orchestras like the New York Philharmonic (and the repertory they play) in the nineteenth century and the mass culture that took its place in the twentieth. He has created a music that mirrors and exalts the public wisdom.