THE HIMALAYAS are at the brink. They jut out from the land-based solid world into another, to thin space and distort time and squat and rise from an area they've rendered, up until lately, inaccessible and unexploitable. But they are there, and because they are people are scaling them and breaching them. Their delicate ecology and their inhabitants age-old existence is being squeezed into a different mold. The mountain world of India, Nepal and Tibet is sliding from what it was, and still is in pockets, into what it will become. The Snow Leopard documents this change.

In September 1973 George Schaller and Peter Matthiessen began a 500 mile trek from the Himalayan town of Pokhara to the unspoiled Crystal Mountains and back. Schaller, an ethologist, went to research mating behavior among a wild herd of bharal, the blue sheep of the Himalayas. He wanted to confirm his speculations that the bharal are a living, missing link between the true goats and the true sheep. He also wanted to see the snow leopard, the most elusive, and one of the rarest, cats in the world, which preys on the bharal. He accomplished both.

Matthiessen didn't join Schaller as an assistant or as a co-researcher. He is not a scientist per se, but a writer, one of the world's best bird-watchers, and a professional traveller. He has journeyed through South America, lived among a stone age tribe in New Guinea, and with turtlehunters in the Carribbean. The Himalayan trip was more than just another notch in his belt. Matthiessen is a Zen Buddhist and Nepal is the navel of his world.

The Snow Leopard is a day by day account of the expedition, told soley from Matthiessen's point of view. It is an account of presence, in every sense of the word. The two men move through space and over distance, from Westernized civilization to its outposts and beyond. The author never met Nepalese or Tibetans completely isolated from the world outside their valleys, but he comes close. For Matthiessen, at least, this is a journey to the core. Time has no meaning in a land where the past is no different than the future, where there is only the present. As a Zen Buddhist, his goal is to live only in this present which he feels he does--when he meditates in clear mountain light, sitting beneath whirling raptors, eating sparse, rough food. Such moments, though, are rare and far between. More often than not the truer reality that he yearns for, and has travelled so far through the years to find, is obscured and bogged down by his observations and actions which he feels are less real, and less the true essence of his being.

IRONICALLY just these observations allow the reader to understand what Matthiessen means and how he can come by his beliefs and his escapes. The Himalayan world he depicts is the enactment of his religion. Seen through Western eyes the Himalayan people calmly progress through prayers and days alike, buffetted by little and infrequently alarmed. Their life isn't meaningless, but neither is its meaning marked. It just is, which is precisely Matthiessen's point.

The porters and sherpas who lead and carry for the two man expedition lug 70 pound loads of lentils and rice and books up snow-choked passes, wearing wool rags at best, and sneakers. Yet, they rarely express their pain or discomfort, though they often stall and procrastinate. They are living proof that Buddhism, at least for Buddhists--which the porters are--works. And since Matthiessen enters their world, it can work for him, too--up to a point.

Matthiessen reveals a lot in The Snow Leopard. Thoughts of his second wife, who died of cancer, linger on. She joined him late in the lifelong search that took him throughout the world and into the realm of hallucinogenic drugs. Together they tried everything, enjoying the experiences but never satisfying themselves. Not until Debra discovered Buddhism did they pause long enought to consider it, above their other choices, the answer. And though it did't solve all their problems--marital or emotional-- it brought some amount of order, and what Matthiessen believes is peace and understanding.

What stands out more than their conversion, though, is the confusion that preceded it. Only in retrospect can he call it confusion. Whatever Matthiessen was doing at any given time made as much sense to him then and held as much meaning as Buddhism holds for him now. Buddhism works differently, but really is no different than anything else he has tried. He hasn't really changed.

Even though Matthiessen believes that the answer to being his raison d'etre, is locked up within himself, at his core. He has to search to find that inner self, to "come home." The expedition is a search, his meditations are a search, even his writing a book is a search. None of the three take place in the present. The expedition was planned and executed. It didn't just emerge; it wasn't just there. Nor is meditation anything more than an active pursuit of self-knowledge, while writing is looking backwards. Putting pen to paper involves memory, and memory is linked to thought. By recalling his thoughts Matthiessen reveals not just what he was thinking but that he was thinking which means, in turn, he wasn't simply being.

Whether or not Matthiessen realizes he is caught in this bind of his own making is unclear. He does, however, know that though he walked away from Crystal mountain a somewhat changed person he didn't walk away a transformed man, as he set out to do. He knows that the snow leopard confounded him.

Buddhism tells Matthiessen that when he is ready to see a snow leopard he will, that one will appear, and that if one doesn't, it is because he is not ready. Yet, unable to practice the restraint he should, he is disappointed when he doesn't see the feline; worse yet, he knows his disappointment is wrong.

It is as if his whole life and upbringing work against him. The Western way is to seek--seek and ye shall find. Schaller baits a cat, and though he doesn't see that one, he later sees another one. Buddhism preaches just the opposite--ready yourself and it will come, you will perceive. These two tenets ensnare Matthiessen. He is too locked into his new-found Buddhist ways to question them. At the same time, he is too locked into the Western tradition to accept Buddhism without having to try to adopt it--which seems to defeat the purpose.

This conflict dominates The Snow Leopard, but only beneath the surface. The only reason it emerges at all is because Matthiessen has written a flawless book. He has explained life as he saw it and lived it, as a man among wonders. Whether he is able to become one with them or not is immaterial to the working of the book, though it is not immaterial to the working of the man. Through his descriptions, observations and perception, Matthiessen is able to blend history and culture, religion and nature ceaselessly and perfectly. Nothing is out of place, nothing is missing.

In telling us who he is, what he did and where he went Matthiessen makes the expedition, and the country and the way of life he visited so briefly, tangible and real. He has explained a religion as well as he has described his journey, and he has described his trek as well as any explorer could ever hope to.

The hike alone was an achievement; the book shows that. But the book itself is an even greater one. It accomplishes what Matthiessen tried so hard to gain for himself. Even though it is about mountains a world away five years ago it is a narrative of the present, it takes the reader that close.