Sometime this fall, lawyer Joel Aurnou will try to convince a jury that former Madeira School headmistress Jean Harris is a woman "from another era" who believed only marriage or suicide could resolve her 14-year love affair with the man she is now accused of murdering.

"She saw only black and white, not grey," said her defense attorney, maintaining that the 57-year-old educator from McLean clung to a "magnificant obsession" and was a victim of her own strict, moral code. Harris could not extricate herself from the doomed relationship with famed diet doctor Herman Tarnower, Aurnou said, even though she knew the wealthy physician would never marry her.

Despondent and filled with self-loathing, he said, Harris went to Tarnower's opulent Westchester mansion the night of March 10 to commit suicide, not murder.

Now, he said, Jean Harris has only one reason to live: "To prove to the world that she didn't mean to harm the man she loved." The man ended up sprawled on the floor of his bedroom, sht four times by Harris's gun.

Charged with second-degree murder in the slaying of Tarnower -- a 69-year-old cardiologist and author of the best-selling "Complete Scarsdale Medical Diet" -- Harris, who pleaded not guilty to the charge, is not likely to testify at her upcoming trial, according to Aurnou. Nor will she be talking to the press or selling her life story to Hollywood.

"We've had a lot of offers," he said. "But shes so private she won't do it."

Since the shooting, Harris has remained a virtual prisoner in her Westchester County home of friends. She flew to Florida last week for her father's funeral, he said, but has avoided being seen in public. Aurnou described his client's state of mind as "fragile" and "suicidal," saying she was still under psychiatric care and still in love with the memory of Tarnower.

Aurnou disputes the theory that Harris had become jealous over Tarnower's relationship with his 37-year-old assistant, Lynne Tryforos, which prosecutors say was the motive for the killing.

"There was no love triangle," said Arnou. "He'd been dating other women for as long as she'd known him. Nobody's focused on the real issue -- Jean Harris's state of mind. Why she was depressed and why she wanted to do away with herself."

In a two-hour interview this week, the baldish, bespectacled self-described "scrappy" lawyer who says he has never lost a murder case in his 21-year career, provided a preview of what promises to be a dramatic trial "of interest to all women." The trial date will be set Monday during a brief hearing in Westchester County Court.

Pacing the floor and stabbing the air with a cigar, Aurnou reconstructed the day of the shooting in an impassioned question-and-answer session. Jean Harris -- not Hermon Tarnower -- he said, was the victim.

"She never intended to kill him," he said. "Jean went there to commit suicide. There was a struggle. He tried to take the gun out of her hand. Four shots were fired."

Tarnower, in a pair of beige pajamas, was found lying between twin beds, bleeding to death. He had been shot four times, Aurnou gestured, once in the base of his right thumb, twice in his right arm and once behind his right shoulder. The murder weapon, police said, was the .32 caliber revolver Harris had purchased at a Tysons Corner sports shop in 1978.

"If she had intended to kill him," Aurnou said, "why weren't there any shots to his head, chest or torso."

Harris made several incriminating statements to the police shortly after the killing, according to court papers. She said she had driven up that day from Madeira, intending to have Tarnower kill her. She said she would not return to Virginia alive.

According to court papers, Harris blurted out: "He slept with every woman he could. I have been through hell with him. I wanted to die. Why should he die? I think I have killed him. He hit me. He hit me a lot. Why didn't you kill me. Hi?"

Aurnou said he will move at the start of the trial to block those statements from being introduced as evidence. He would not say if he will seek to quash other statements police said Harris made: that she threw the gun into the bathtub at one point during the confrontation, and that she had a slip of paper with names of her close relatives to be notified in the event of her death.

A cruical piece of evidence will be the registered letter Harris mailed to Tarnower the morning of the shooting and retrieved by Aurnou at a Scarsdale post office before police and prosecutors could get hold of it. ("That was quite a coup," Aurnou said.)

The defense lawyer also managed to pick up several suicide notes Harris wrote the day of the shooting that were left in her brick cottage on the sprawling Madeira campus.

That evidence is expected to butress Aurnou's claim that Harris intended to do away with herself, not Tarnower.

Aurnou said he will try to convince the jury that Harris was a middle-aged, divorced, career woman with no self-esteem. "A 57-year-old woman who had lost all faith in her appearance," he said. She was so psychologically scarred by slights and "put downs," and had suffered the pain of insecurity for so long, that she was driven to self-hatred and despair, he said.

On the day of the shooting, Monday, March 10, Aurnou said, something happened at the Madeira School which "made her snap." He would not reveal what had caused Harris to become upset, only saying that "to you or I, it wouldn't have meant much." But to Harris, it was the last straw, Aurnou said.

It happened, the lawyer said, after she had written and mailed the letter to Tarnower. She remained in her Madiera cottage that afternoon. A school colleague, he said, knew Harris was upset and placed a small bouquet of flowers on the front seat of her car, not wanting to disturb the headmistress.

Aurnou gave the following account of the shooting:

Sometime that afternoon, Harris called Tarnower and told him she was coming up to visit him. Then she put, on her mink coat, carried the .32-caliber revolver to her blue and white Chrysler and drove to Tarnower's home, five hours from Washington.

When she arrived at his $500,000 estate, she walked inside and up the stairs, carrying the gun in one hand and the bouquet of flowers in the other.

Harris reportedly asked her lover to kill her. There was a scuffle, and Tarnower hit Harris in the mouth, saying, "Get out of here. You're crazy." tApparently trying to grab the gun from her, Aurnou said, Tarnower was shot four times. When asked later by police who pulled the trigger, Harris said she didn't know.

Was it an accident? Aurnou wouldn't use the word. "There's no crime here unless she intended to kill the doctor," he said. "That's what the jury has to decide."