A truly original opera makes a rare appearance

"Someone must set it to music."

Composer Alban Berg feverishly spoke these words after attending the Viennese premiere of the play "Wozzeck," by the German dramatist Georg Büchner , in May 1914. By "someone," of course, Berg meant himself, and eight years after seeing the play, he had produced one of the most searingly original operas ever composed, a summit of 20th-century music.

"Wozzeck" has been absent from Boston's musical landscape since 1987: The last time it was heard was a concert performance by the Boston Symphony Orchestra on April 21 of that year. Tomorrow night, 20 years later to the day, the New England Philharmonic allows us to hear it again. It, too, is a concert performance, in celebration of the orchestra's 30th anniversary.

Büchner's play, left unfinished at his death in 1837 and not published until the 1870s, sounded themes of Expressionism before their time. The title character is a poor soldier with a girlfriend named Marie, with whom he has an illegitimate son. His position in society is one of constant humiliation: He has to perform a series of degrading tasks for his captain, and to earn extra money he submits to medical experiments at the hands of a sadistic doctor. As the play progresses he becomes increasingly unstable, hearing voices and seeing strange visions. When he finds out that Marie has been unfaithful to him, his one genuine human relationship collapses, and his mind with it. Wozzeck kills Marie in a jealous rage and later drowns, trying to find the knife with which he stabbed her.

At the play's center is the theme of society as an inhuman, uncaring force that crushes the individual who doesn't fit within its order. One of the things that makes the opera so fascinating is that Berg responded to this theme of nightmarish alienation with such rigorously structured music. Like Wagner, he symbolized characters and situations with musical leitmotifs; unlike Wagner, he fit them into a series of musical forms then thought to be outdated -- sonata, rondo, scherzo, and trio -- and molded them to fit the dramatic action. In Act II, Wozzeck encounters the doctor and the captain, who tease him about Marie's infidelity. The scene is set as a complex fugue for the three voices, their conversation swirling about the horrible truth that Wozzeck gradually comes to realize.

Putting the opera together must be taxing, to say the least. It calls for a large orchestra, chorus, and children's chorus. There are 12 characters, and the principal roles are especially difficult to sing. The musical language is a unique hybrid of tonal, atonal, and serial elements.

Richard Pittman , the Philharmonic's music director , says that the score is also dense and constantly changing in response to the dramatic situation. "Much of the time there are at least three or four, sometimes five, different independent lines going on at once," he says by phone. "I've got a lot of experience doing modern music, but this is a difficult piece to learn."

For all the musical complexity, though, Berg remained unshakably focused on the drama while composing "Wozzeck." His goal, he famously wrote, was "simply to return to the theater what is the theater's." Of his ingenious formal devices, he continued, "there must not be anyone in the audience who . . . notices anything of these various fugues, inventions, suites. . . . Nobody must be filled with anything except the idea of the opera."

Pittman finds something similar. "There's a funny dichotomy," he says. "There is this very carefully worked out musical structure, but what you're really aware of, at an instinctive level, is how incredibly the words are set."

Still, one of the most intense episodes has no singing at all. There is an extended orchestral interlude that follows Wozzeck's death and precedes the opera's final scene. Here the music is at its lushest, in true late-Romantic style. All the leitmotifs heard previously return, summing up the tragic action that came before. The music builds to a devastating climax in the key of D Minor, as Wozzeck's own motif is heard for the last time, before subsiding.

But what follows is even more wrenching. In the final scene, a group of children, including Wozzeck's son, is playing when a boy excitedly announces that Marie's body has been found.

"Hey!" one of the kids says to Wozzeck's child, who's playing on a hobby horse. "Your mother's dead."

Wozzeck's child continues riding. "Hop hop! Hop hop!"

As the children run off to view the body, he hesitates. "Hop hop!" Then he follows the others. Now an orphan, he can assume his father's place in society , the monstrous cycle beginning again.

At Tsai Performance Center, Boston University, 8 p.m. 617-353-8725, nephilharmonic.org.