Teeming with Mayan ruins, poisonous snakes, missionaries and anthropologists, the Lacandon rain forest, largest in the hemisphere north of the Amazon, stretches across southern Mexico and into Guatemala. It is home to 400 Lacandon Indians, heirs to the lowland Maya civilization that dominated the Yucatan Peninsula and Central America 12 centuries ago.

The forest is being devoured now by bulldozers, lumberjacks, land-hungry farmers and ranchers. But long before the last trees are felled, the Lacandon Indians will have joined the sad recessional that marks the extinction of primitive tribes. Already, as Robert Bruce notes in the introductory chapter of this book, there are more publications about the Lacandon than there are Lacandon.

Bruce, an anthropologist and linguist, has studied the Lacandon since 1956, lived with them, learned their language, and is, he believes, the only outsider ever to participate in their most sacred rite. It is Bruce's controversial argument that the Lacandon, whose primitive lives are based on hunting and slash-and-burn agriculture, are the direct cultural descendents of the advanced Mayans whose architectural and artistic genius can be seen at monumental ruins like Tikal, Copan, Chichen Itza and Palenque.

But "The Last Lords of Palenque" is no academic treatise. Bruce provides the necessary background on the Lacandon, then turns the book over to Victor Perera. Perera is a mosaic of cultural experiences more complex than the Lacandon themselves: a Sephardic Jew, born in Guatamala where his father ran a department store, raised by Indian servant women. As a boy, he saw five bewildered Lacandon Indians who had been spirited out of the jungles to be exhibited like monkeys at a national fair. He was educated in the United States, has roamed the world as a journalist, and lives and teaches in California. At times, he sounds like a Californian out of a comic strip: Save the whales, save the trees, open your head, get in touch with your body, trace your roots. But his background and interests form a sensitivity poised to vibrate like a tuning fork in the presence of an ancient people under cultural and ecological siege just a few hundred miles from his birthplace.

It could have led to a maudlin work, beseeching us to shed abstract tears for a romanticized race of noble savages. But there is nothing abstract, nor romanticized, about these Lacandon. Through Perera, we come to know an amazing variety of human responses to a society's final crisis. Perera converses with drunks and charlatans, craftsmen and fallen women, irrepressible children and ancient storytellers. We also meet the outriders of the forces that are destroying the Lacandon -- the self-assured missionaries whose individualistic preachments corrode Lacandon solidarity; the mahogany loggers destroying the Lacandon habitat. They are not villains, only somewhat limited humans proceeding according to their own lights, or just following orders.

Perera reacts to them all. The Lacandon women arouse him and he tosses in his hammock with sensual dreams, remembering the musk of the Indian women who cared for him as a child. He drinks the ceremonial balche' with the men, trades lascivious jokes with them and weaves unsteadily back to his hut. He harvests corn in the milpas carved from the jungle with machete and torch. He brings back gifts -- .22 ammunition, pocket knives, Bic lighters. He gossips with the Lacandon, and learns enough about their tangle of marriages, separations and spats to people a television soap opera. He tells loggers that cutting the forest could make the polar ice caps melt and they look at him with the bored expression of bureaucrats who've heard it all before.

Most of all, he listens to Chan K'in of Naha', the t'o'ohil, religious and civic leader of the northern Lacandon. Chan K'in is the center of the book, as he is of his community, the inexhaustible repository of the Lacandon myths and fables, the interpreter of dreams. Mayan material culture may have been lost, but its spiritual and mystical richness lives on in Chan K'in. In his eighties, he still works his milpa, and the youngest of his three wives still bears him children.

Perera visited the Lacandon three times during the two years of the loggers' final assault on the forest around their community. His is a unique and respectful portrait of a proud people on the edge of the abyss, and of an ancient culture suddenly exposed to all the paraphernalia of Western civilization -- airplanes, radios, jeeps, foreign film crews.

There is a deterministic view that the impersonal and inevitable spread of technology dooms such a culture. But the Lacandon show that technology is not the problem. They can borrow a new technology and adapt it to their culture. But they cannot adapt to the destruction of their forest. It is not the Bic lighter that dooms the Lacandon, but the determination of others to exploit their land.