?I feel very lucky, but I also feel helplessly entangled. It?s just gotten too big, and too much,? says the author of ?At Play in the Fields of the Lord,? ?The Snow Leopard? and many other books.

?Given my druthers, I?ve often just wanted to live on a boat where you?re confined to one single cabin, with just one room, and by definition you have to cut everything away.?

He won?t do it, of course. Can?t do it. Not with a wife, Maria, who likes the place just fine and a group of fellow Zen practitioners who meditate with him daily; not with the whale?s skull and countless other artifacts to be found around the house, or the writing loft that features pictures of George Plimpton, Ben Bradlee and other friends.

?The absurdity of life,? Matthiessen once wrote, ?does not relieve one of the duty . . . to live it through as bravely and as generously as possible.? A Zen Buddhist since the 1960s, he regards the world as transient, but precious, worthy of his full, inspired attention. The world, meanwhile, has rewarded him back.

He is a man of letters who helped found The Paris Review ? the celebrated literary quarterly ? who wrote the acclaimed novel ?At Play in the Fields of the Lord? and two classic works of nonfiction, ?The Snow Leopard? and ?The Tree Where Man Was Born.?

He is a leading environmentalist and wilderness writer who has sweated and shivered in the deserts of Africa, hitchhiked across South America and endured a hurricane in Antarctica. He is a longtime liberal who befriended the late farm union activist Cesar Chavez and wrote a defense of the Lakota tribe, ?In the Spirit of Crazy Horse,? that led to a highly publicized, and unsuccessful, lawsuit by an FBI agent who claimed Matthiessen had defamed him.

At age 77, the author remains a lean, rugged figure, his gray-white hair matted and sweaty on this warm afternoon, his face weathered but not weary, his car of choice a pickup truck, his current literary project a task that could alone fill a one-room cabin.

In the 1980s and 1990s, Matthiessen published a trio of novels ? ?Killing Mr. Watson,? ?Lost Man?s River? and ?Bone by Bone? ? about a community in Florida?s Everglades at the turn of the 20th century and the predatory planter, E.J. Watson, who becomes the most feared and famous resident.

The Modern Library plans to reissue those books, informally known as ?The Watson Trilogy,? in a single volume. But like Joyce Carol Oates, who last year completely rewrote an early novel, ?A Garden of Earthly Delights,? Matthiessen is essentially preparing a brand new book. The narrative will be revised, condensed and reorganized.

?It wasn?t meant to be three books,? he says. ?I think the end pieces are very strong, but the middle section, while in my view had the best material, was too long. I didn?t like it, so I wanted to do it properly.?

His editor at the Modern Library, Judy Sternlight, said that some characters and story lines will have to be discarded. The problem becomes how to eliminate sections that ?unto themselves are lovely, but don?t necessarily help tell us who E.J. Watson was.?

Matthiessen spends hours each day on the Watson project, which the Modern Library hopes to publish in 2005 or 2006. Otherwise, he meditates, plays tennis, rides his bike a half mile to the beach along the Atlantic Ocean, swims, goes fishing and ?tries to more or less stay fit.?

Superficially, his life resembles a man he despises, George W. Bush. Like the president, he is the son of a wealthy Republican, a graduate from Yale University and an outdoorsman most at home in open spaces. But there?s a Buddhist word for Matthiessen?s view of Bush: ?Avcidya,? applied to one still bound by greed and passion. ?People like the Bushes take great pains to shelter their children from the harsher aspects of life,? Matthiessen says. ?And that?s very bad. People should be exposed to that.?

The author himself has tried to live out a modern version of the Buddhist legend, a rich kid transformed by the discovery of suffering. Matthiessen was born in New York in 1927, the son of Erard A. Matthiessen, a wealthy architect and conservationist. ?The Depression had no serious effect on our well-

insulated family,? the author later wrote. But at age 14, his life changed when he served as a counselor at a charity camp and recalled his first dinner, with a group of boys a year younger.

?They had their supper laid down on the table in front of them ? corn on the cob and hot dogs and all the fixings, of course,? he recalls. ?And they fell on it like wolves! I mean they?ve never seen anything like it ? not only eating it, but grabbing each other?s extra and stuffing themselves.

?And I realized these kids had never been able to relax and eat their fill in their whole life. . . . It was so grotesque that a lot of them were sick to their stomachs all night long. They had gorged, literally gorged. And I thought, ?What kind of country is this where we have all this money and people are as poor as that?? ?

A writer-adventurer was born. While at Yale he wrote the short story ?Sadie,? which appeared in Atlantic Monthly, and he soon acquired an agent. After graduation, he moved to Paris and, along with fellow writer-adventurer George Plimpton, founded The Paris Review.

?Everybody was terribly excited about it ? the idea of running a small magazine in Europe,? recalls Benjamin Bradlee, former Washington Post executive editor and a friend of Matthiessen?s in Paris. ?Peter was extremely attractive, articulate, amusing, liked a good time, terribly serious about his work. . . . He was broke, as we all were, and he was struggling to make ends meet.?

But Paris only reminded Matthiessen that he was an American writer, and in the mid-1950s he returned to the United States, moved to Long Island?s historic Sag Harbor village, socialized with Jackson Pollock, Willem de Kooning and other painters, operated a deep-sea fishing charter boat ? and wrote.

Matthiessen?s early novels were short, tentative efforts: ?Race Rock,? ?Raditzer? and ?Partisans,? which features a wealthy young man who confides that ?his ignorance of human misery had been consigned to him with as much loving care as an inheritance.?

In 1961, Matthiessen emerged as a major novelist with ?At Play,? his acclaimed tale of missionaries under siege from both natives and mercenaries in a South American rain forest. At 373 pages, the novel was far longer than his earlier books and its detailed account of a man?s hallucinations brought him a letter of praise from Timothy Leary, the LSD guru.

?The first three books were very economical and very careful,? Matthiessen says. ?With ?At Play,? I wanted to go to wilder places, and wanted to go the edge a little bit. And I pretty much have stayed out there.?

He has since written more than a dozen books, including ?Far Tortuga,? a novel told largely in dialect about a doomed crew of sailors on the Caribbean; ?The Tree Where Man Was Born,? an acclaimed chronicle of his travels in East Africa; and ?The Snow Leopard,? his introspective account of a trek to the Himalayas that won the National Book Award in 1978.

?I?m not the only writer around, I know, who?s said that his dream one day is to write something even a tenth as exacting as ?The Snow Leopard,? ? says Paco Iyer, author of ?Video Night in Kathmandua? and other travel books and editor of ?The Best American Travel Writing 2004.?

?Matthiessen tells us that on every real adventure into the natural world, nothing less is at stake than the soul itself. And that takes courage, as well as the honesty that finds fault first in the world with himself.?

Matthiessen doesn?t seek to conquer Earth, but to preserve it. In 1959, he published his first nonfiction book, ?Wildlife in America,? in which he labels man ?the highest predator? and one uniquely prone to self-destruction. Much of his fiction, from ?At Play? to ?Bone by Bone,? bestows a lionlike aura upon nature ? grand when respected, dangerous when aroused, tragic when exploited.

?In his own lifetime . . . the river has changed from blue to a dead gray-brown, so thickened with inorganic silt that a boy would not see his own feet in the shallows,? Matthiessen writes in ?Lumumba Lives,? a short story set around New York?s Hudson River.

?For a long time, by the riverside, he sits on a drift log worn smooth by the flood, withdrawn into the dream of Henry Hudson?s clear blue river, of that old America off to the north toward the primeval mountains, off to the west under the shining sky.?

He records change everywhere, even at home. He purchased his 6-acre property in 1959, for the now fire-sale price of $35,000. Over the decades, he has taken an old garage and chicken coop and converted it into his main house. The meditation house, which comfortably seats more than 20, used to be a stable. His writing studio was once a children?s playhouse.

Meanwhile, Sag Harbor has grown around him, evolving from quiet artist colony to prized resort community. The dirt path Matthiessen once rode to the ocean is now paved. The high hedges aligning his estate muffle, but do not silence, the sounds of cars hurrying by.

?I think of it, of course, in terms of when I first came here, 45 years ago, when it was all farmland and the farmland came right back to the dunes and the fishing was really extraordinary and there was nobody here between Labor Day and Declaration Day (July 4). It was just silent, ideal, for a writer ? or a painter,? he says.

?When people tell me how much they like it here, I tell them, ?You should have seen it then.? ?