OSHKOSH, WIS., NOV. 7 -- On the stand, her hair parted neatly to the right, her hands resting comfortably on the chair arms beside her, the witness answered the prosecutor's questions, one by one. She said she was born in Seoul, South Korea. She said she did not know her natural parents. She said she came to this country as an infant, that she was 27 years old, that she was raised in Iowa City by adoptive parents, and that from the time of her childhood she had heard the sound of voices that seemed to be arguing inside her head.

"Sounded like battling, I couldn't understand," the witness said. "Occasionally I would hear a voice that would sound like it was somebody right next to me, talking in my ear."

In the courtroom the television cameras had been pulled from the front row -- turned off, as the judge had ordered, and set on the floor so the witness would not see them and feel alarmed. The spectators pushed together on the courtroom benches, a few of them perched on folding chairs brought in to offer extra seats; the line to get in had begun to form at sunrise for a seat on Day 3 of the trial, the day the woman called S. would take the stand.

In the line the spectators had argued, offering opinions of their own: He had raped her, he had not raped her, he had taken advantage of her, he knew what was wrong with her, how could he possibly have known? "This is not a circus," Judge Robert Hawley had announced when court began this morning, gazing down through his glasses at the crowd on the benches. "This is a very sensitive case. There may be some bizarre behavior that you have not witnessed before."

The spectators nodded and were quiet. Some of them balanced writing tablets on their laps and took notes. District Attorney Joseph Paulus stood before his witness, his voice conversational. "Do you have any personal knowledge as to the events in the park?" he asked.

"No," his witness said. "I do not."

"Who would be in the best position to talk about the events in the park that night?" Paulus asked.

"Franny," the witness said.

"Would it be possible for us to, uh -- " Paulus paused -- "meet Franny, and talk to her?"

"Yes," the witness said. "Now?"

"Yes," Paulus said. "Take your time."

The witness closed her eyes. The courtroom was utterly quiet. The witness's chin dropped gently to her chest, and for perhaps five seconds she sat without moving, a slender young woman in a short-sleeved cotton sweater and calf-length pale blue skirt.

She lifted her head again, and opened her eyes.

She looked at Paulus with interest, taking him in.

"Hel-lo," she said.

"Franny?" Paulus asked.

A hundred people, in the Oshkosh courtroom with the blinds pulled down to keep away the distraction of the morning sun, leaned forward to listen to the voice that had just introduced itself as Franny. For two days, psychiatrists and mental health workers had been filling the record, in this spectacularly unusual rape trial, with explanations of a psychiatric illness called multiple personality disorder. "Split personalities," was how the attorneys summarized it the morning the trial began, as they pulled from the jury pool the seven men and five women who now form the jury in State of Wisconsin v. Mark A. Peterson, a felony sexual assault case.

Peterson, a married 29-year-old grocery worker, is charged with violating a Wisconsin law that makes it a crime knowingly to have sex with a person mentally unable to assess his or her own conduct. He has never denied having a sexual encounter last June with the woman who later brought charges against him, but his defense attorney has argued from the outset that Peterson did not believe the woman he had sex with -- a woman these articles have referred to as "S.," to protect her privacy -- was mentally ill.

This morning, for the first time, Paulus put her on the stand.

She had come to court as "S.," and walked briskly to the witness chair. She had taken the oath from Hawley, her right hand raised. She had spoken precisely and clearly, saying "Yes," or "No," or "I don't recall," in a clipped voice that betrayed no emotion at all. She had said her adoptive father was killed when she was 20, and that she and her mother found his body; he had been repairing an automobile at home, she said, and the jack apparently slipped. The car had crushed him.

"I knew that he was dead," S. had said evenly. "I went inside and called the police."

Paulus had asked for no further details on her father's death, and when he asked about her childhood she had said only that there was much she did not recall; she was certain there had been abuse, S. had said, but she was not sure what form it had taken. "I know it was physical from my father, and mental from my mother, but I am not sure of what nature."

Now Paulus began the process the spectators had lined up outside to watch: He had promised to summon some of S.'s 46 personalities, and Franny was the first.

Paulus stood, watching the young woman who sat blinking before him. "Good morning," she said. "Or good afternoon -- which is it?"

Her voice lifted -- not dramatically, but enough to put a new lilt into the ends of her words. Her eyebrows and face seemed to work more vigorously, as though someone had given a tiny tug on a string attached to the top of her head. Her carriage, the set of her shoulders, looked unchanged.

"It's, uh, morning, actually," Paulus said. "How are you today?"

"I'm fine," the young woman said. "How are you?"

Paulus said he was fine too. "I was just talking to {S.} moments ago," he said, using his witness's legal name, "and I'd like to talk to you about what happened June 9 of 1990. But before we do that, the judge has to talk to you."

From the bench, Hawley looked down at the young woman's dark hair. "Franny," he said, "I'd like you to raise your right hand for me, please."

Steadily, his face impassive, Hawley swore Franny in. "So help you God?" he said. "Yes," she said, and looked at Paulus. Paulus asked her what she and her downstairs neighbors -- S.'s downstairs neighbors -- had been doing the night she met Peterson.

"We fished," the woman said. "We took turns. Well, John was there -- I think Jamie was there ... Jennifer was there, but I don't think she caught a fish."

Paulus did not ask who John and Jamie and Jennifer were. According to his own opening statement and the testimony of his psychiatric witnesses, they are separate identities among the scores of personalities S.'s body is supposed to contain; Jamie is a woman, John an intent fisherman, and Jennifer a 20-year-old woman who likes Bob Seger and Michael Jackson but is unschooled in the ways of the world.

Had Peterson come by, Paulus asked? His witness said yes. Could she remember what they had talked about? "Most of it was small talk," she said. "I recall telling him that we were many, there were many of us in the body. I said we were multiple, that we shared the body. I told him about some of the others."

Paulus wondered whether he had reacted.

"He didn't seem surprised," the woman said.

Paulus and his witness talked for a while about what happened that night -- how she gave Peterson her telephone number, how he came to her house two mornings later and invited her for breakfast, how she agreed to have coffee with him and talked with him at the restaurant about her multiple personalities. When they got in his car, she said, Peterson asked her about one of the personalities she had already described to him.

"He asked, 'May I talk to Jennifer, the one who likes to have fun?' " the witness said. "And I said, 'Of course.' So I went away. And I assume Jennifer came out.' "

"Do you have any personal knowledge of what happened after that?" Paulus asked.

"No," the witness said.

"Do you think we could talk to Jennifer today?" Paulus asked.

"Yes," the witness said. "Now?"

"Sure," Paulus said.

The young woman closed her eyes. Her head dropped again, just for a moment. When she opened her eyes she coughed, looking momentarily confused, and looked at the judge. In a voice so small it almost squeaked, she said, "Excuse me, could I have a drink of water, please?"

Hawley handed her a cup. "Hi, Jennifer," Paulus asked. "How are you?"

The woman's eyes opened a little wider, and she smiled. "O-o-okay," she said.

"You know me, don't you?" Paulus asked. "What's my name?"

Her voice high, she fairly sang it out: "Joe!" she cried.

Paulus asked if she remembered the judge and the defense attorney. "Hi," the woman said. Paulus waved his hand toward the jury. "Remember I told you in my office two days ago that you were going to come down to court and tell about what happened?" he asked. "I told you there'd be a jury of people who would listen to what you had to say."

The woman studied the jury. "A bunch of people who decide," she said.

"That's right," Paulus said. "These people, right here."

"Hi," the woman said, and waved. Several jurors, looking uncertain, lifted hands to wave back. "I want to talk to you about a time when you were in a car with Mark Peterson, and you asked Franny to go away -- " Paulus began.

"Who?" the woman asked.

Paulus pointed toward Peterson. "The man right there," he said.

The woman looked at Peterson, who looked back, his face blank. "Oh," she said. "Yeah."

"How is it that you came out that day, when you were in his car?" Paulus asked.

"He asked for me," the woman said, in a tone that indicated the answer should be obvious. "So Franny came and got me."

"What did you think when you saw this man you didn't know in the car with you?" Paulus asked.

"Nothing," the woman said, her voice still light and quick. "He seemed like a nice enough man."

Paulus asked what the man had done as they were driving on the road together. "He put his hand on my leg," the woman said, "and said, 'Can I love you, Jennifer? Can I love you?' "

Paulus asked what she thought that meant.

"Well, when you love somebody, you like them an awful lot," the woman said. "And you care about them. And you take care of them. And you're nice to them."

"And what did you respond?" Paulus asked.

"I said, 'Yes,' " the woman said.

Paulus wondered what happened next, and the woman said he touched her -- "started feeling my boobs," she said. "And down there. Where you're not supposed to touch, Emily says."

Emily, according to earlier testimony by S.'s therapists, is a personality who is approximately 6 years old and sometimes eats crayons that the other personalities are then obliged to spit out.

"He stopped the car," the woman testified. "And he slid the front seat back, and he told me to take off my shorts -- so I did."

Paulus asked her why she thought he wanted her to take her shorts off.

"I dunno," the woman said.

"Why did you take them off?" Paulus asked.

Sounding impatient now, the woman spoke faster: "Because he told me to."

She said he took his own pants off, and that he climbed on top of her. She said she did not understand what he was doing, that it hurt, but that she did not say anything. "I couldn't," she said. "His shoulder was in my mouth."

She couldn't talk very well, Paulus asked?

The woman began to cry a little. "He kept slobbering all over me," she said. She said Peterson told her that it felt good, and that when he said that she knew what she was supposed to do. "I seen it on TV," she said. "People wiggling like that. And when a person says it feels good, the other person is supposed to say it feels good. So I put my arms around his back, and I said, 'That feels nice.' "

Paulus asked her whether it had.

"No," she said. She sounded perplexed. "But you're supposed to say that, aren't you? It was on TV."

Peterson told her, she said, that it was time to stop what they were doing. "Don't want you getting pregnant," she testified Peterson said.

"Do you know what that means?" Paulus asked.

"I know what pregnant is," the woman said quickly. "It's when a guy sticks his finger in your belly button and a baby comes out."

She told Peterson she could not become pregnant anyway, she said. "I said, 'I can't, because {S.} got her tubes tied," the woman said. "And he said, 'Well, that's one thing off my mind.' And then we drove down 20th Street, I don't know where we were, and he said, 'Can I have Franny back?' So I went back inside."

Paulus moved closer to the witness stand. "Franny -- " he began.

"Jennifer!" she cried.

"Sorry," Paulus said. "I slip once in a while."

"That's okay," the young woman said. "Everybody makes mistakes."

Paulus asked the woman whether it was true, as psychiatrists reported earlier this week, that the personality called Emily had been "peeking" at the time of the sex. "Would it be possible for me to talk to Emily this morning?" he asked.

"Emily?" the woman asked. "Okay."

"Take your time," Paulus said.

The woman closed her eyes, then opened them again. "Wait a minute," she said.

"What's wrong?" Paulus asked.

"She wants Pooky," the woman said.

"Pooky?" Paulus asked.

"Her bear," the woman said.

A courtroom aide handed the woman a small brown and white stuffed bear. The bear in her left arm, the woman lowered her head, waited, and raised it to open her eyes. She looked hurriedly around the courtroom. "Wow," she said.

The voice was markedly higher now, and she waved at Paulus. "Hi, dipshit," she said.

The woman burst into giggles. "Hi," Paulus said. "Why did you call me that?"

The woman put one hand over her mouth. "Sheila told me that if you like somebody -- " she began, and then cried, "Oh! I forgot. She told me not to say that."

"It's okay," Paulus said. "My feelings aren't hurt."

Paulus asked her if she remembered about coming to court and talking about what she had seen, and also about the judge who would listen to her.

The woman looked up at the judge. "The big shot?" she asked.

"Hi, Emily," Hawley said. "Do you swear that the testimony you are about to give here -- "

"I don't get big words," the woman said.

"Okay," Hawley said. "Do you promise to tell the truth?"

"Yes," the woman said. "Nothing but the truth?" Hawley asked. "Right," the woman said. "So help you God?" "Yes," she said.

The woman told Paulus she had seen what happened the day of the sexual encounter. "I was peeking the whole time," she said. "Even when Franny was out." When they came back to the house where S. lived, she said, she looked at her underwear. "My panties were all gushy and gross, and my bottom hurt," she said.

"Who did you say that to?" Paulus asked.

"Everybody," the woman said.

Paulus asked for Leslie, one of the personalities Emily reported showing her bottom to; the woman closed her eyes, bowed her head, and emerged with a small raucous laugh and a request to tell a joke. "No jokes," Paulus said. "You promised, no jokes."

He asked for Sam, the personality that the woman testified had evolved from a sort of animal that dropped beneath tables and growled when frightened; the woman closed her eyes, bowed her head, and came up speaking in a voice that sounded faintly like one of the colored monsters on "Sesame Street." "How -- is -- my -- speech?" the woman asked.

"Good," Paulus said.

"Sam glad," the woman said.

She was cross-examined as S., and as Franny, and as Jennifer, in somewhat greater detail. "You didn't object to the sex at that point?" asked defense attorney Edward Salzsieder.

"Tell me what sex is, and I'll tell you if I objected or not," the woman said in what she had told Salzsieder was Jennifer's voice. "I don't know what you're talking about."

She was still being cross-examined as Jennifer when she complained that she was getting hungry. "I want to go home," she said. Salzsieder said he was finished, and Hawley called a recess. The woman who had led S. to court leaned over and whispered in her ear, apparently reminding her of something; the woman closed her eyes, looked down for a moment, and came up with eyes open again.

"Okay," she said briskly, in the voice that sounded like S., and started toward the door. "Let's get out of here."