A CAMBODIAN ODYSSEY By Haing Ngor With Roger Warner Macmillan. 478 pp. $19.95

A COLLEGE freshman returned from seeing the latest Vietnam War movie and I asked her how she rated it. Too bloody, she answered, and then added without prompting: "The Killing Fields is still my favorite. I've seen it three times, and cried. It's the one about the people over there."

My friend is not the only young American who considers The Killing Fields the classic Vietnam War movie even though it is not about Vietnam but Cambodia. For The Killing Fields remains the one film about "the people over there," the people of Indochina who fought and suffered through wars we abetted and their own revolutions.

The film tells the true story of Dith Pran, a Cambodian journalist who saved the lives of two foreign correspondents, including his close friend Sydney Schanberg, and was then thrown out into his country's revolution where he nearly perished.

Pran's rare heroism carried the film and the Cambodian actor who played his role won an Academy Award. The actor was Haing Ngor, a medical doctor who lived through the same holocaust as his countryman Pran. Ngor had never acted before and he stole America's heart when he thanked Lord Buddha, among others, at the Oscar ceremonies.

Now Ngor has written his own story, A Cambodian Odyssey, in collaboration with Roger Warner. In his memoir Ngor shows the awful price he paid to play his role so brilliantly. His odyssey is strewn with impossible choices culminating in the deaths of his loved ones, burdening him to this day with the guilt of the survivor.

The story itself is immediately familiar, since Ngor's path through the Cambodian revolution was nearly the same as Pran's. For that reason alone, A Cambodian Odyssey should reach the larger audience denied the other admirable autobiographies by Cambodian survivors. (There are now eight such memoirs in print in English and French, including one by a French wife of a Khmer Rouge official.)

While I cannot judge one survivor memoir better than another, Ngor's well-crafted book could be the most accessible. It makes an unimaginable horror come to life simply because many readers will have seen Ngor act out the revolution on screen. We know how he looked when he scrounged for small crabs in the rice paddies because he did the same thing in the movie. We saw Ngor humiliated by a young Khmer Rouge girl, we saw his face twisted in pain when beaten and we heard his heart-breaking sobs at the death of a young boy.

The common points between Pran and Ngor are historical. Both were intelligent, middle-class professionals who watched their country fall apart up close: Pran reported the civil war, Ngor treated its wounded. At war's end, in l975, both were ordered out of Phnom Penh in the forced exodus of all 2 million inhabitants, the first postwar cruelty of the victorious Khmer Rouge.

They were sent to the Northwest Zone of Cambodia where they joined thousands of other middle-class Cambodians who had been classified as "new people," Cambodians who had not supported the communists during the civil war. Overnight these new people became peasant farmers, members of a supposedly classless society where manual labor was used as an instrument to transform character.

But classes were not destroyed. A new hierarchy developed with the "new people" at the bottom. They were treated like wild animals, not peasants. Their lives did not count, as the Khmer Rouge told them, and an uncountable number died.

NGOR BEGINS his book: "Nothing has shaped my life as much as surviving the Pol Pot regime. I am a survivor of the Cambodian holocaust. That's who I am."

But Ngor also wrote that after reading the movie's film script he realized he was Dith Pran too. I have to disagree. Perhaps no one but a survivor could have portrayed Pran and understood Pran's story. Pran was a hero who stood up to the Khmer Rouge; Ngor would know the special terror Pran had to overcome.

But as individuals the two men are very different and my guess is the differences inspired Ngor as much as the similarities inspired Ngor's unforgettable performance.

Both men were offered seats for their families on the last American helicopter out of Phnom Penh in 1975. Pran put his wife and children aboard and stayed behind to help Schanberg cover the war. Ngor declined the offer for himself, his wife and his mother-in-law. Neither man knew then the tremendous consequences of that single decision. For the remainder of the revolution Pran did not have to worry about his family -- Ngor watched his die.

When the two men first encountered the Khmer Rouge each was instantly faced with a life-or-death situation. Pran stepped forward and begged, pleaded, with the Khmer Rouge to save his friends' lives. Ngor was performing surgery when a Khmer Rouge soldier marched in and threateningly demanded to see the doctor. Ngor denied his profession and fled from the hospital. "We took a last look at the poor young soldier on the table," Ngor wrote, " . . . he was going to die."

The truly heartbreaking episodes come later, in the last, most insane period of Khmer Rouge rule. Ngor's father was caught "stealing" scraps from a communal rice pot -- a crime punishable by death. Ngor witnessed his father's arrest. "I froze," he wrote. "My father turned his face and looked sadly into mine . . . He wanted my help." There was nothing Ngor could do; his father signalled him to go away. "Numbly I obeyed," he writes; he never saw his father again.

The worst death was the last. Ngor's wife was expecting their first child. During her seventh month of pregnancy she went into early labor. Ngor, a gynecologist, realized his wife needed a caesarean delivery, which he could perform. But he had already been tortured hideously three times by Khmer Rouge determined to force him to admit to being a doctor.

He decided he could not deliver the baby himself. "If I {did} the neighbors would know, the {spies} would find out and that would be the end of me." He searched out a trusted midwife who told him to perform a caesarean. Ngor whispered, "Cannot." His wife implored him, "Save my life. Please save my life." She died in Ngor's arms, their baby died in her womb.

Could there be a worse torture than this?

The Khmer Rouge murdered Ngor's family and friends -- he was not responsible for nor could he have saved all their lives. But he is a survivor, they are not. Normally when describing the Khmer Rouge revolution one lists the casualties: as many as 2 million deaths directly resulting from the revolution; the destruction of Cambodia's society and economy; the initiation of a war that led to Cambodia's invasion and occupation by Vietnam. After reading memoirs like Ngor's one realizes that this is a partial accounting. Also include the survivors who will be forever crippled by their memories. :: Elizabeth Becker, a writer living in Paris, is the author of "When the War Was Over: The Cambodian Revolution and the Voices of its People."