Marsha Norman hadn't intended to write " 'night, Mother," the play that last week won her the Pulitzer Prize for drama. She hadn't intended to write anything that summer of 1981, as she and her husband left their Louisville home for the Upper West Side.

"I was terribly nervous," she says, recalling how she worried about the move. "It wouldn't be quiet. I'd miss my friends. I'd miss how easy and green Kentucky is. If something happened to your car or your teeth, you are surrounded by people who couldn't wait to help." Her plan, therefore, was "to do nothing but order draperies and unpack."

Enter a character that Norman, wincing about how "mystical" she sounds, calls the Guiding Writer-Self. The GWS, seeing the opportunity in Norman's newfound isolation and empty calendar, "somehow is aware that 'this is free time, Marsha.' " (In Norman's impersonation, the Guiding Writer-Self is a finger-wagging nag). " 'You may think you have boxes to unpack. But you have free and clear time to write.' "

So Norman spent the summer at the typewriter, in a study that overlooked the gate of the Dakota where John Lennon had been shot to death. By Halloween, she had created a wrenching 90 minutes in a rural house in which a woman named Jessie cleans a pistol and almost cheerfully informs her mother that, after their usual Saturday evening manicure, she will kill herself.

Last week, as Norman was sitting on the porch of an inn north of San Francisco, finishing a cup of coffee and staring at the Pacific, the innkeeper appeared to say that her husband, Dann Byck, had called from New York with "urgent and exciting news." " 'night, Mother," Norman's fifth play and the first to reach Broadway, had won the Pulitzer. Byck, who produced the play, dispatched enough champagne for the guests in the inn's dining room. Norman and her fellow escapees had "a wonderful, quiet but very happy evening," she glows. "That's exactly how you want to hear about something like that. You get to keep it to yourself for a little while."

No more. Norman is back in New York, after working with a San Francisco theater to present a revision of an earlier comedy, fielding phone calls and spending hours in interviews in a publicity firm's offices above Broadway.

Despite all those years in Louisville, teaching disturbed children, working for a state arts program, editing a children's page (dubbed the Jellybean Journal) for the Louisville Times, at 35 she's entirely convincing as a Manhattan playwright. A citified, gray-green ensemble of tweed blazer, high-necked lace blouse and velvet skirt sets off russet hair falling over green eyes. Her voice is husky, perhaps from the cigarettes she lights, and purged of any accent. Years ago, she says, she realized that people with drawls were expected to say stupid things about predictable subjects ("like pancakes") and deliberately flattened hers. She serves on panels and Dramatist Guild committees with "Wendy" (Wasserstein) and "Lanford" (Wilson) and Arthur Kopit and Chris Durang, all the other New York playwrights who've gone beyond "promising" to produceable, and finds their communal presence exhilarating. "If Michael Weller is doing something really extraordinary I'm encouraged to take extra risks," she explains. "We benefit from watching each other walk down the path, d'you know? We all understand that we don't always have to be good, but we have to keep trying."

Yet the process of imagining and writing her plays has changed little, Norman says, since she was back home teaching or editing by day and writing by night. "It always begins with a memory of a moment of extraordinary intensity: a moment I was in great pain, or a moment when I was desperately afraid, or a moment when I was in awe of an act of courage. An emotional memory so strong it has survived all the intervening years and is still able to move me."

She won't reveal what memory prompted " 'night, Mother"--"that's mine." But she adds, "I knew almost immediately that it would begin, 'I'm going to kill myself, Mama,' and that the suspense would come not from what was going to happen, but how."

Imagining the ensuing conversation, as Mama rages, ridicules, banters and bargains, consumed Norman for months. "It's like having house guests," she muses. "Jessie and Mama have moved in. When they've been there a few days, you know whether they make their beds in the morning and how they take their coffee. After a few weeks, you know how they feel about their brothers. After a few months, you know what they think about their lives. It's quite possible to be having supper with your husband and be interrupted by these imaginary people. I sit there at the table and hear lines of dialogue or suddenly understand why something is so."

She remembers feeling cold that summer. "Marsha does not write about middle-class concerns; she writes about dying, coping and being alone," notes Jon Jory, producing director of Actors Theatre of Louisville, which presented Norman's first four works. "She's only written one character who was interested in money or material things, and that was a pimp" in "Getting Out," a play she wrote at Jory's invitation that later had a long off-Broadway run and lots of critics' attention.

By September, with most of the play on paper, Norman called on Anne Pitoniak and Kathy Bates, both Actors Theatre of Louisville veterans, for a read-through so that she could hear how it sounded. "We all cried"--and " 'night, Mother" had acquired its eventual cast. There were further revisions after readings at the Circle Repertory Company: Norman had to work in pauses for audience laughter. "I was surprised--but overjoyed--to learn that the play was so funny." She thinks the humor was her own way of coping with the suicide she was creating. "I needed to break the tension. But you can't always break the tension for the audience"--so she edited out some of the laughs. " 'night, Mother" opened this winter in Boston at Robert Brustein's American Repertory Theatre before its New York opening capped a two-year effort by Norman and Byck.

His involvement as producer exacerbated their preoccupation with Jessie and Mama, directors and lighting designers. Byck had prompted the move to New York; heir to a chain of posh department stores, he wanted a new career in commercial theater, "a classic mid-life crisis that shocked everyone in the community," his wife says. As a result, "there was so much at stake all at once. My new play. His first production to reach Broadway. We had to make some very serious agreements that for this one day, or for this dinner, we'd talk about anything else but the play. And then," she laughs, wearily, "there'd be these long silences . . ."

Both have moved on to new projects this spring. Byck is assembling another production, affording Norman the delicious pleasure of speculating about directors and cast for someone else's play. She and composer Norman L. Berman are collaborating on a musical called "The Shakers," which she has suggested be retitled "What You Learn About Love in a Celibate Society."

She is growing a trifle anxious about it. It's been nearly two years since she began thinking about the book and lyrics, and two years is as long as Norman feels able to pay attention to any project. "That's about how long I remain the same person and remember what it was that first confused or saddened me."

Besides, she is no longer the newcomer with the cleared calendar who could walk and shop and never have to hear people ask how her new play was proceeding. "People are already telling me, 'You're going to have another Pulitzer,' " she sighs before rushing downtown to another appointment. "What a cruel thing to say."