ON AUGUST 28, 1948, near the end of a fierce civil war that took more than 150,000 lives, 41-year-old Eleni Gatzoyiannis was executed by Communist guerrillas occupying the Greek mountain village of Lia. Her "crime" was to have arranged for her 8-year-old son and his older sisters to escape from the village so that they would not be numbered among the thousands of Greek children who were forcibly separated from their parents and sent to the Soviet Union or the Communist-controlled sector of East Europe. In this remarkable, utterly compelling book, the surviving son recreates the life of a woman who, like most civilians in war, died primarily because she happened to be in the wrong place at the wrong time.

Nicholas Gage's powerful narrative is likely to disturb many readers because the author explicitly states that revenge--the desire to track down and punish those directly responsible for his mother's death--provided the main impetus for his research. By making this admission, Gage has broken the powerful modern taboo against attributing any legitimacy to revenge, on either a personal or social level.

Because the word "vengeance" conjures up such disreputable associations, Gage would have been more politic, albeit less honest, had he followed the usual course of insisting that he wanted only "justice, not revenge."

But the conventional formula would have rendered the book much less illuminating, because Gage's personal quest--which ultimately emerges as a subtext in the larger story of his mother's life and death--affords a fascinating example of the ways in which retributive impulses may be put to constructive rather than destructive use.

An experienced investigative reporter and former Athens bureau chief of The New York Times, Gage used his formidable detective skills to unearth the facts concerning his mother's death. The truth turned out to be extremely complex, involving not only the misfortune of an ordinary family trapped in an ideological and military struggle but the restrictions on a woman's scope of action in a traditional, male-dominated peasant culture.

Eleni Gatzoyiannis' life--devoted to carrying out the rigidly prescribed duties of a village daughter, wife and mother--was not unlike the lives of most women throughout history.

Eleni was married in 1926 to a man who spent most of their married life in the United States--coming home to father children, returning to Worcester, Massachusetts, when his money ran out. On his American earnings from a half-interest in a vegetable stand, Christos Gatzoyiannis was able to support his family handsomely in the impoverished economy of rural Greece.

This way of life was extremely common not only in Greece but throughout southern Europe in the decades between 1900 and the outbreak of World War II. When Christos and Eleni were married, he wanted his wife to accompany him to America, but she refused because it was a woman's duty to care for her aging parents. This was the first of many female choices that helped trap Eleni in the circumstances that led to her death.

"But no matter how far the men went and for how long," Gage writes, "it was the responsibility of women, their roots deep in the earth, to protect the family name and village traditions. Anastasia Lollis had married in 1911 and lived with her husband only a year before he sailed off to America, where, returnees said, he had acquired a wife and family in Chicago. But Anastasia still waited for his return and would continue to wait for more than 70 years.

"Women went into labor and gave birth alone, or tried to abort themselves with herbs, wooden stakes and heavy rocks if a pregnancy occurred during a husband's long absence. Even if the seducer was a bride's father- in-law, the ruler of her household, she would get no mercy."

In 1940, after giving birth to four girls, Eleni finally had a son--the crowning achievement of a Greek woman's life. Shortly afterward, Greece was engulfed by the Second World War and Christos, who was back in America, was no longer able to send money to support his family. During the war years, Eleni's main concern was finding enough food for her children--especially the baby Nikola, whose age made him especially vulnerable to the effects of malnutrition.

Gage's account, based primarily on extensive interviews rather than his own incomplete childhood memories, is rich in small incidents that reveal character. In 1944, one of Eleni's neighbors returned from the provincial capital of Yannina with an array of fine clothes and household goods.

The goods came from the homes of Jews, who had been herded together by the Germans and who--their Greek neighbors were sure--would never return.

Eleni refused the gifts her neighbor offered. "No, thank you," she said, "They've gone so many years now without a cap, without a new dress they can wait until the war is over and America opens up. I can't take clothes that belong to people who are being led away to their deaths."

After the war, Eleni was eager to join her husband in the United States but was again stymied by the conventions governing women. Her husband, concerned about what would happen to their daughters' virtue in America, wanted the family to remain in Greece until Eleni had arranged a suitable marriage for their eldest girl. And so the family remained in Lia as civil war approached between the Communists and the royalists.

A friend advised Eleni to move herself and her daughters to Yannina, beyond the reach of the Communist guerrillas who would surely occupy Lia. She refused because "if I went to Yannina, a woman with four unmarried daughters and no husband, everybody would call us whores!"

Christos ordered his wife to remain in her home regardless of what was happening politically. The Communist forces, as he saw them from far-off Massachusetts, were simply countrymen who would leave the villagers alone as long as they deferred, in time- honored peasant fashion to the occupying authority.

There was no way for Christos or Eleni to have known that their countrymen had ideological loyalties that took precedence over tradition. In 1948, as it became clear that the Communists were losing the civil war, mothers in occupied villages were asked to give up their children to be sent to Eastern Europe "for their own protection." One spring day, the 8-year-old Nikola overheard guerrilla officers say that the children would be forcibly taken from mothers who refused to give them up voluntarily. When he reported the officer's words to his mother, her worst fears were confirmed.

To save her children, Eleni risked much more than gossip. After arranging an escape plan for Nikola and three of his sisters, she remained behind in an effort to help her fourth daughter, who had been conscripted for service by the guerrillas.

When the guerrillas learned that four of the Gatzoyiannis children had escaped, Eleni was arrested, tried and eventually shot. Her conviction was aided by testimony from some of her fellow villagers, who envied the relatively secure financial posoition she had once enjoyed as the wife of an American citizen.

Gage's account of the Communists' role in his mother's death is likely to raise some political hackles. After all, more recent Greek history offers examples of abuses perpetrated by the right-wing military junta overthrown in 1974. However, there is no more reason for Gage to give ''equal time" to right-wing atrocities than there was for Jacobo Timerman to accompany his account of imprisonment in Argentina with a history of torture in Castro's Cuba.

Gage, who was sent to Athens by The Times after the fall of the junta, was clearly outraged when some young Greeks suggested that the pedomasoma--the forcible separation of children from their parents during the civil was--was only a right-wing myth. The rewriting of history is, of course, a favorite occupation of both right- and left-wing ideologues. Gage is neither.

At the end of the search, Gage actually found the Communist judge who sentenced his mother to death. The outcome of the confrontation (which, since this book has certain detective elements, I will not reveal) is, paradoxically, both anti-climactic and satisfying. For Gage's real achievement lies not in tracking down those who actually ordered his mother's death but in re-creating her life.

Hampered by an upbringing that made her delay action until it was almost too late, Eleni Gatzoyiannis managed to behave honorably and save her children so that they could join their father in America instead of growing up as orphans in Eastern Europe. By bringing her individual spirit and her world to life, Gage has achieved both justice and revenge.