WESTERN WRITERS are usually so horrified by Calcutta that they rarely get beyond their own reactions. The city and its millions of poor are described from above, sometimes vividly and passionately, but almost always from a Western frame of reference, in terms of population, rupees earned per day and causes of death. The descriptions often read as if the writer has visited a slum, collected statistics, then left. That in itself is numbing, which may be one reason why there are so few good books on a city that haunts and confuses nearly everyone it touches. Even the most complete study up until now, Geoffrey Moorhouse's Calcutta, treats the city's idiosyncrasies as quaint, and in the process, condescends.

The City of Joy by Dominique Lapierre breaks from this tradition. Lapierre did not just visit the poor, he spent three years researching and living among the residents of one of the worst slums in one of the most impoverished cities on earth. He has actually managed to describe the poor from their own point of view. This is a remarkable feat.

Until now, Lapierre has been the master, with co-author Larry Collins, of a heavy- breathing style of contemporary history, turning out the best-selling pot boilers O Jerusalem, Is Paris Burning? and Freedom at Midnight. But now Lapierre, working alone, has turned away from Mahatma Gandhi, Lord Mountbatten and the other historical figures who dominated the Indian fight for independence in Freedom at Midnight. Instead, he has focused on heroes of another kind, the anonymous poor. This book, too, has put him on the best-seller list in France, Italy and Spain. Its translation from French into English has been awaited in America and India as well.

The City of Joy makes fascinating the commonplace events in the lives of the poor -- from bathing in the streets to the massaging of babies to (perhaps not so commonplace) the emasculation ceremony of a eunuch. Yet Lapierre moves beneath their simple existences and uncovers a nightmare of emotions and awful choices.

Selima, a desperate young mother, decides to sell her unborn 7-month-old fetus for use in a Western laboratory, even though she feels the abortion will be murder. "But then there were other voices too that haunted Selima in the night," writes Lapierre, "the familiar voices of her three other children crying out with hunger. At dawn she made her decision." She died of a massive hemorrhage during the operation.

Anand Nasar, translated as the "City of Joy," is a slum of 70,000 people in the bowels of Calcutta, christened "either out of ignorance or defiance" by a jute factory owner. Here the lives of the ree main characters -- a Polish priest, a rich young American doctor and a Bengali rickshaw puller -- all connect.

The priest comes to devote himself to god and the poor. The doctor joins him for a year, at one point fainting after he performs amputations on hundreds of lepers in the street. He recovers to see a dog carry off an arm. The rickshaw puller comes with his family to find work in Calcutta after his fields have been destroyed by drought.

Anand Nasar, three times the size of a football field, has "the densest concentration of humanity on this planet." Carbon dioxide and sulphur fumes kill at least one member of every family. The heat beats down eight months a year, only to be relieved by a monsoon that makes alleys and shacks into "lakes of mud and excrement." Leprosy, tuberculosis, dysentery and hunger are rampant.

Yet in the midst of this, Lapierre finds that people transcend their condition, becoming "models of humanity" who ''know how to be tolerant of all creeds and castes, how to give respect to a stranger, how to show charity toward beggars, cripples, lepers and even the insane. Here the weak were helped, not trampled upon."

But Lapierre sometimes over-romanticizes the struggle of the poor (he continually refers to their slum as "the City of Joy"), diminishing their real pain and integrity. In one chapter, the priest is kept awake at night by the cries and groans of a young Muslim boy dying of osteotuberculosis next door. He takes the boy a vial of morphine but claims to find him so at peace -- "how could such serenity radiate from that little martyred frame?" the priest asks himself -- that he decides there is no need for the painkiller. Unless a miracle was occurring, this sounds strange.

At another point, Lapierre approvingly quotes the doctor's father as saying that "a simple smile can have as much value as all the dollars in the world." One suspects the residents of the City of Joy might disagree.

Lapierre has also used long paragraphs of translated interviews that are too slick and too close to his own writing style to ring true. The orginial 200 interviews are said to have been translated from Hindi, Bengali and Urdu into English and French. Since the book itself has now been translated into English, it is hard to know what went wrong. But it is certainly unusual to hear someone who buys blood from the poor of Calcutta exclaim, "Holy mackerel!" or to hear a rickshaw puller declare that "if you think it's easy to get one of these jalopies moving, you've got another think coming."

UNLIKE Freedom at Midnight, The City of Joy has no source notes. The book's protagonists "wished to remain anonymous," Lapierre says in an author's note. Therefore he has "changed the identities of some characters and certain institutions," leaving the reader puzzled over what is real and what is not. Since several of the book's characters eventually die, one wnders whether their thoughts are conjecture by the author or second-hand from another source, or did Lapierre interview them before they died?

We are also never told when the events in The City of Joy took place. There is a reference to the 1976 American Bicentennial, but 110 pages later India is setting off its first nuclear explosion, which occurred in 1974.

In the end, the sensation of floating between ficton and fact makes The City of Joy less effective than it might have been. One of the characters dies the very night of his daughter's wedding, after literally going hungry to be able to afford it, but the story would have been more evocative if the reader could be sure that it happened that way.

Yet The City of Joy is full of basic truths. Some of its moments may stay with a reader forever. Who can forget the dying rickshaw puller selling his bones to a man who makes money from exporting skeletons, or the poor of Calcutta washing the body of a friend, and weeping during the riverbank cremation ceremony? This book contains great lessons of resilience and dignity, and of what is really important when life is pared down to its essence. The City of Joy will make anyone a little richer for having read it.