Fifteen minutes before the curtain would rise for the world premiere of his first produced play, "The Day Room," Don DeLillo, looking pallid -- even ashen -- paced the Harvard University hallway of the Hasty Pudding Theater. Nervous as a groom in the wings of a church, the 50-year-old novelist, whose themes are the crossed wires of American paranoia, whispered, "Getting married was easy!"

Fiction writers (Saul Bellow, Norman Mailer and William Styron among them) are seduced by drama because the theater appears to offer a live forum for argument -- and glittering opportunities to examine the most intimate tenets of characters' reasons for being. So it is for the American Book Award-winning author of "White Noise."

"The idea of writing a play is attractive to a novelist," DeLillo said at the theater, where a production of his play will end this week as part of the American Repertory Theatre's New Stages program. "We want to get out of the room and have contact SW,-2 SK,2 ld,10 with other humans, face to face."

Novelists usually put every point they think important explicitly into the narrative of a play. But, according to theater critic and American Repertory Theatre Artistic Director Rubert Brustein, DeLillo is a "natural playwright." Says Brustein, "The really exciting thing about performing his play is it brings out values you don't get in reading it. DeLillo buries layers of ideas and actions for actors to extrapolate."

Michael Bloom, director of "The Day Room," says that "a novelist's play almost always reminds an audience just how important language is to the theater, and brings an entirely new voice to the theater, a unique approach to words and images."

In their odyssey of developing "The Day Room," DeLillo and Bloom have crisscrossed the country during the past year. Script-in-hand readings by actors, with critiques by invited audiences, began in New York at the Manhattan Club and Playwrights Horizons. Subsequently, more intense but similarly noncommercial workshops of DeLillo's new play took place in Utah at Robert Redford's Sundance Institute.

Each reading and workshop has been a search for a second act. The first act of "The Day Room" was written by DeLillo in two weeks. "I simply had an idea and I saw characters on a stage." The first act "was like transcribing a dream," DeLillo says.

Working in theatrical communities has given DeLillo more support. Brustein believes DeLillo discovered "a whole new aspect of himself" -- and learned to "trust the machinery of the stage -- the actors, set, lighting and costume designers." And each reading and workshop, plus interpretations by a repertory company in rehearsal for production, alternatively stimulated and provoked DeLillo, as he puts it, to start "rewriting, again and again and again."

Rewriting "The Day Room" and an earlier unproduced play called "The Engineer of Moonlight," DeLillo found that scripts for the stage must be written in the emotionally distinct shorthand of dramatic language. The most economical and effective language may, in fact, be an actor's nonverbal gesture.

The Bronxville, N.Y., writer is a notoriously private person, who shuns appearances on daytime television to promote his eight published novels. "I've always lived as if in a cave," DeLillo has said, only half in jest. And he says, "I have my obsessions, my ideas, but I don't know from where, I run into them when my characters run into them."

Both DeLillo's latest novel, "White Noise," and his new play reflect a visceral sense of reality to be feared and laughed at -- and difficult to explain. In "White Noise," something undefinably horrendous appears imminent, yet DeLillo's Professor of Hitler Studies and his wife are providentially anchored in their middle-American, suburban supermarket of reality. As the professor's colleague observes, "Here we don't die, we shop. But the difference is less marked than you think."

For DeLillo, writing for the theater appears to have been artistically as well as personally liberating. It has allowed him to collect many concerns of his novels, sharpen and breathe the presence of acting into them. Among DeLillo's legion of obsessions in "The Day Room" are fear of death, the imbecility of jargon and television newspeak, and the illegitimacy of bureaucratic authority.

The danger in drama is that DeLillo's obsessions could become Vices in a modern morality play -- without any Virtues to play against. But DeLillo's comic sense rescues his characters in "The Day Room." In a hospital room, Budge likes to talk; his roommate Wyatt is a laconic man, in for "tests." Doctors and nurses appear, their apparently plausible "real" personas unravel and dissolve. As the head nurse, who previously has been a model of common sense, is hauled back to an adjoining mental ward by orderlies, she protests, "The person in the uniform controls the facts. They prove truth is possible."

In the second act, the same persons as different characters exist in the day room of the mental ward, which they now believe is a motel room. In their "unreal estate," Wyatt in a straitjacket spiels television-speak and is switched on and off by others in the room by means of a station-switching remote control device.

Should an actor in "The Day Room" break down on stage and the company walk off, or if an overwrought Harvard Law School student suddenly shouted, "Fire!," a majority of the audience would probably believe these events to be logically connected to the wired, wired world of DeLillo's play. In fact, during the final scene on opening night, a smoke alarm accidentally went off and the audience seemed to believe it was part of the play.

Reactions of Boston critics to "The Day Room" were generally positive. The Boston Globe found it "not an average comedy, nor is it easy to describe . . . But for the most part this is an unselfconscious, fizzing, inventive black comedy that is also enormously funny." The Boston Herald called it "an intellectual mystery, a metaphysical comedy, an absurdist riddle. And even if you can't make heads or tails of it, you can enjoy its tantalizing ambiguity."

For his part, Brustein says he's "eager to see a play every year from DeLillo." DeLillo's play will be published this fall in American Theatre magazine, and director Bloom says he "would not be surprised to see a regional theater mount another production" of "The Day Room," though no booking is yet scheduled.

Meanwhile, DeLillo himself has returned to his own room -- to finish a novel.

Patrick Flynn is a playwright and former president of the Boston-based Playwrights' Platform.