(FORTUNE Magazine) – There are seven of us dragging our luggage through the airport in Rio de Janeiro, preparing to board the first of three planes that will eventually deposit us on a bumpy grass landing strip in the midst of a vast piranha- and alligator-filled swamp 1,000 miles away, in western Brazil. "Hats, everybody," calls out the group's leader, who laughingly distributes a bunch of olive-green baseball caps emblazoned with the words CONSERVATION INTERNATIONAL. All of us dutifully plunk them on our heads. We look like a troop of overage Boy Scouts en route to a camporee.

At the end of the line, a suitcase in each hand and conservation cap in place, is perhaps the least prepossessing member of the group: a nice-looking older fellow with the gosh-golly demeanor of a Topeka soybean farmer on his annual trip to Kansas City. You could spend a week with this man, and unless somebody mentions it (he won't) you might never figure it out. He is Gordon Moore, a billionaire ten times over, one of the very richest men in America, a co-founder and former CEO of Intel, the source of that famous prediction about computerdom's growth known as Moore's law, a man who, with his impressive scientific mind and quiet determination, probably did as much as anybody to develop the semiconductor, the microprocessor, and the entire personal computer revolution.

Gordon Moore is not worried about electronics at the moment, however. Now 70, he retired as chairman of Intel more than a year ago, and his immediate concern is probably how many fish he will catch in the rivers of western Brazil. "I could spend half my time trying to outwit a dumb fish," he confesses cheerfully. Four days from now, after hours of fishing in the hot sun, he will cool off by playing a vigorous game of water Frisbee in one of those piranha- and alligator-filled rivers.

He has a more serious concern too. Moore is spending a large chunk of his money and more of his time on a subject perhaps as ambitious as all his other accomplishments combined, though he would be genuinely embarrassed if you made a fuss about it. He worries, quietly, that we are destroying plant and animal species--biodiversity--at an alarming rate. He is trying to save the planet.

You might expect an ecology-obsessed billionaire to be a brash kind of guy who pokes you in the chest to drive home his opinions. But Gordon Moore's concerns are so rational and understated that, like a wise man speaking softly in a noisy room, he makes nearly everybody pause and press to hear more. One of America's most accomplished engineering minds has not been transformed into a granola-eating tree hugger by some band of environmental zealots. If anything, the environmentalists are being transformed by Gordon Moore.

At best, says Moore, the rapid destruction of species will leave earth a far less attractive planet for our children and grandchildren: "Just to keep the place interesting is nice. When you lose a species it never comes back." Moore likes interesting planets. The Iowa-sized swamplands of western Brazil, known as the Pantanal, are one of the richest repositories of plant and animal variety in the world. Moore, on his third trip here, will get almost giddy seeing an anteater sprint by him during one of his dawn walks through the ranch where he's staying. But more ominously, he suggests there's a chance that the complex interplay of myriad species is an essential part of how humans survive on the planet. We could, in effect, unwittingly remove the ecological soup can at the bottom of the grocery-store display and bring a big link in the world's food chain crashing down around us. And with the world's swelling population straining resources at the same time that the destruction of species is accelerating, disruptions could become disasters. "You don't know when you do something that affects a lot," he says. "You play with some variable and mess up an entire ecosystem."

Moore's style is not to rant; even people who have worked alongside him for decades, like Andy Grove, his successor at Intel, barely know of his concerns here. His approach, instead, befits the scientist, researcher, and technologist he is. He and others at Conservation International (CI) think that they have spotted a flaw in how environmentalists and biologists study the environment and how organizations spend money to preserve it. So last year Moore and his wife, Betty, quietly committed $35 million to CI to create a worldwide confederation of scientists, economists, political scientists, and the like to collect and share information on new ways to preserve biodiversity.

Whatever you do, don't call his creation (which set up headquarters in Washington, D.C., this year) "the Moore Center." Not unreasonably, Peter Seligmann, chairman and co-founder of Conservation International and the fellow who distributed those conservation hats in the Rio airport, proposed doing just that. "It was one of the biggest donations ever made to conservation," says Seligmann. But Moore would not allow it--he feared naming the organization after himself would discourage others from getting involved. "It's not the Moore Center," he insists one afternoon in the Pantanal, in the closest he ever seems to come to getting annoyed. "It's the Center for Applied Biodiversity Science."

For a person who never lectures, preaches, cajoles, or threatens, and who avoids the limelight as though it were a death ray, Gordon Moore, on a seven-day road trip, is a paradoxically effective ambassador. The day before heading off to the Pantanal (where he helped persuade some big landowners to sell land and development rights to CI), he arrived in Rio to attend a meeting with the leaders of Brazil's top timber and papermaking companies. Seligmann and CI officials based in Brazil have spent months trying to get them to change the way they run their timber operations. The companies have stopped cutting down virgin forests along the Atlantic, says Seligmann, which is good. But their vast plantations of eucalyptus trees don't support a large variety of birds, reptiles, and mammals. Would they consider planting a more animal-friendly mix of trees and vegetation amongst the eucalyptus, he wants to know. Seligmann thinks the new Not-the-Moore Center will be able to help them find ways of doing it without disrupting logging.

Through most of the meeting, Moore sits silently, mouth slightly open, in rapt attention. Only when the executives digress into a complaint about the short fiber length of some varieties of eucalyptus does Gordon pipe up, joking about how tough the wood is: "Gee, when I try splitting eucalyptus logs at home, the fiber sure seems long to me." The timber execs, who look as if they wouldn't know which end of an ax to hit a tree with, are intrigued by the idea that one of the world's richest men splits his own firewood. (It's not clear what they'd have thought if they knew he flies coach, shops at Costco, and trudges off to Nordstrom when his wife affectionately points out that he needs "more neckties to spill food on.")

The mood lightens. Moore talks a bit more about eucalyptus trees in California. The conversation shifts back to biodiversity. Seligmann presses for cooperation. The executives cautiously agree to set up their own research center that will work with the (Moore) center to determine which new plantings will work best.

As always, it is hard to put a finger on just what Gordon Moore did at the meeting. Afterward, when asked what his strategy had been, he shrugs. "I just decided to let Peter [Seligmann] do all the talking. He knows a lot more about this than I do. They were looking at things that were pretty far along, so I sat as an observer." But you get the sense that perhaps the CEOs of these companies would not have come if Moore had not been there. They seemed aware, too, that this septuagenarian had spent more than 16 hours traveling from San Francisco to Rio and had barely stepped off the plane before heading to the meeting.

It would be easy to believe that Moore's low-key, nudge-things-along style doesn't accomplish much. You won't hear anything about his scientific and business achievements from Moore. He never brags, and in voluminous oral histories compiled by Intel, he rarely uses the word "I," preferring to give credit to everyone around him, as though he were erasing his fingerprints from everything he has touched. "He is a genuinely humble person," says Tom Everhart, former president of the California Institute of Technology, where Moore has been board chairman for more than a decade. Bobby Inman, former head of the National Security Agency and another Cal Tech board member, describes Moore's style as that of a "shepherd--rarely speaking up, never pounding the table, but always able to move a roomful of large egos in the proper direction."

It is not surprising, then, that Moore's role in commercializing transistors and creating the integrated circuit and the microprocessor was often overshadowed by those of more glamorous figures like Robert Noyce, the co-founder and first CEO of Intel, or Andy Grove, Moore's hard-nosed successor. Moore, throughout his career, has been subtle, undramatic--and highly effective.

It was Moore, for instance, who played a decisive role in making tiny high-tech spinoffs the business model for Silicon Valley. In late 1955, Moore, a recently graduated Ph.D. chemist, was recruited to Mountain View, Calif., by William Shockley to help design and make semiconductors. Shockley eventually shared a Nobel Prize for having invented the transistor at Bell Labs a few years earlier. But as head of Shockley Laboratory, he proved a nasty and unproductive manager. After a year of frustration, Moore helped lead a rebellion in 1957. He and eight others, including Bob Noyce, quit en masse. They got the backing of a company called Fairchild Camera & Instrument and formed Fairchild Semiconductor, an enormously inventive and successful chipmaker. With Noyce as the unit's flamboyant and peripatetic vice president and Moore its quiet head of research, Fairchild came up with inventions that laid the groundwork for the chip industry, including making chips by etching and printing components in layers, and the "integrated circuit," in which components with different functions were etched and connected on the same sliver of silicon. It was at Fairchild that Moore came up with Moore's law, an insight that the number of transistors per computer chip (a rough measure of a chip's power) was doubling every 18 months. That simple rule of thumb (since revised to a doubling every two years) has become so much a part of Silicon Valley culture that it is the standard by which the entire industry paces itself.

Despite such triumphs, Moore and Noyce got fed up with Fairchild Camera's intrusions into their operations; they bolted in 1968 to found Intel. Its accomplishments, of course, are legendary. One engineer realized Intel could eliminate a lot of special-purpose chips by taking one chip and using software to make it perform multiple functions. Thus the microprocessor was born. And when IBM chose an Intel microprocessor for its fledgling personal computer back in 1981...well, you know the rest.

Anyone looking for lightning bolts of technical brilliance from Gordon Moore during his years at Shockley, Fairchild, and Intel would be disappointed. There really weren't many, says Arthur Rock, the venture capitalist who served as Intel's first chairman. "It was Bob Noyce who had strokes of genius," says Rock. "But he couldn't stick to anything. Gordon was the opposite. He didn't invent things, but he clearly saw the way to get somewhere. He more than anyone else set his eyes on a goal and got everybody to go there." Moore succeeded Noyce as CEO in 1979. He led the company partly by being patient. Engineers could plop down uninvited beside him in the cafeteria and in 15 minutes get insight into a problem that had bedeviled them for years. Moore even calmed the hard-charging Andy Grove. "In the early days, I was a hotheaded 30-year-old, running around like a drunken rat," says Grove. "Gordon knew what he was doing, and he guided me. He was a kind of Uncle Gordon."

In 1987, Moore retired as CEO and became chairman. "I was getting lazy," he explains. "I got tired of jumping on a plane at the drop of a hat and flying around the world to meet with a customer." He stayed in that job until 1997, coming to work three days a week in the later years, weighing in less and less often on the minutiae of designing semiconductors. It was the perfect time to look for something new. (He appears not to have gotten too out of touch, though. In a casual aside during a speech on chipmaking to alumni at Cal Tech last year, he pointed out that "the power is the frequency, proportional to the capacitance, which is one over the scaling factor squared in capacitance per unit area times the area times V squared." As if everyone didn't know that already.)

To anyone who knows Moore and Conservation International, it shouldn't be a surprise that they found each other. Moore has been an avid outdoorsman all his life. He frequently travels halfway around the world just to drop a fishing lure in some obscure patch of ocean. His wife, Betty, is similarly hooked. She recalls that early in their marriage, when their two sons were infants, they would park alongside rivers in Northern California and take turns catching fish: "One of us would stay in the car with the children, and the other would fish. Then we'd switch." Last year Moore and Selig-mann went fishing off the Golden Gate. Moore was so intent that they bag their limit that he barely noticed that the waves were picking up, or that the navigation aid on his 32-foot boat had drifted off its setting. "There were 12-foot seas as we were heading back," says Seligmann. "The waves were so high we couldn't see the buoys. I wasn't sure we would make it."

It was on their fishing trips to faraway places that the Moores began to realize that once pristine hideaways were getting spoiled. A favorite spot, Cabo San Lucas, at the southern tip of Baja California, went from "a sleepy little village where the main road was a dry creek bed" to "high rises and golf courses," he complains. Fishing villages in Costa Rica and Panama have been spoiled too. To the Moores, these were signs of more widespread destruction. "When you see the impact humans have on the earth..." he says. "We're seeing extinction of species faster than at any time since the dinosaurs."

Moore appears to have been drawn to Conservation International at first sight. He says he was introduced to Seligmann in the late '80s by John Young, then CEO of Hewlett-Packard. By 1990 he had joined CI's board of directors.

Conservation International's approach to environmentalism is a complex and sophisticated one, and the organization has attracted other big-name corporate chieftains to its board. Says William Ford, chairman of Ford Motor: "What I like about CI [is that] they are zealots about saving the environment, but on top they are sound scientists. They are passionate, very bright Ph.D.s, not Luddites. They get things done in a quick and big way." Other CI bigwigs include Disney's Michael Eisner, Hyatt's Nicholas Pritzker, and Seattle billionaire Craig McCaw.

Peter Seligmann, who founded CI a year before Moore got involved, had been head of international programs for the Nature Conservancy, a powerful U.S. nonprofit that buys up tracts of land for preservation. Seligmann, 48, a graduate of the Yale School of Forestry, quit in 1987 to pursue the vision that became CI: a novel and highly focused approach to preserving species. He and his new organization seized on research showing that a vast portion of the world's biodiversity was located on a tiny fraction of its land, and that these areas, now known as hot spots, need particular protection. "About 60% of the plant and animal species are found on less than 2% of the land," says Seligmann. Not surprisingly, most of these hot spots are in tropical climates, in South America, Africa, and Southeast Asia.

For Americans living in cooler, temperate areas, it is hard to appreciate how vulnerable plant and animal life in those tropical places can be, especially since they appear to be incredibly lush and fertile with giant, fast-growing vegetation that could overrun Manhattan Island in a week. How could any animal fail to survive where mangoes and coconuts forever dangle an arm's length away?

Alas, it's a jungle out there in the jungle. And in the wetlands. And in the rain forests. Appearances to the contrary, the soil in such places is actually incredibly poor. When tropical plants and animals die, they don't fall to the forest floor and slowly decay into rich soil as they do in New Jersey. Instead, in the humidity, rain, and year-round heat of the tropics, some bug or spore or seed quickly seizes on a dead bit of organic matter and turns it back into something that lives and is nurtured aboveground. Life is supported not by Mother Earth but far more by an astoundingly complex interaction of all the birds and monkeys and fungi and vines and jaguars and beetles nearby. Because there is no single rich source of nutrients, every plant and animal has to be highly specialized to eke out a living from its neighbors.

The result, in all its glory, is biodiversity. Toucans have funny curved beaks not so they can appear on boxes of Froot Loops, but so they can hang upside down and grab the innards of a seed pod that is accessible only from below. That's nothing. There is a fungus in Africa (Cordyceps myrmecophilia) that can't reproduce well in the darkness of the rain-forest floor. What to do? It actually nestles on the back of a certain ant (Paltothyreus tarsatus), sends shoots down into the animal's nervous system, and somehow causes the ant to have the overwhelming urge to climb to the top of a nearby tree. In the treetops the fungus flourishes. The ant, alas, dies, probably wondering how the hell it wound up at the top of a tree.

The threat to these biodiverse hot spots is, of course, man. Sometimes the humans are rich and appallingly greedy, like the lumber companies that suddenly appeared in Third World countries such as Suriname, ripping out trees as fast as they could, or oil and mining companies that spoil vast areas with their crude roads and pollution. More often, however, the problem is the astounding growth of the human population, which propels people, already desperately poor, to invade or degrade hot spots in order to survive.

Rather than organize antibusiness protest marches or lobby to evict humans from the hot spots, Seligmann, through Conservation International, has orchestrated elaborate approaches for saving these areas. Simply put, CI tries to create economic incentives so local would-be toucan eaters are motivated to support conservation instead.

In the Atlantic rain forest of eastern Brazil, for instance, cocoa farmers have unwittingly supported biodiversity for years. Cocoa plants need shade, so farmers leave big native trees growing overhead. Bingo! Everything from a rare monkeylike tamarind to an oddball fungus has a place to live. But cocoa prices have fallen by half over the past 20 years, and desperate farmers have been clearing out their cocoa trees--and the native forest overhead--to create cattle farms. That works fine for about three years; the dead and burned vegetation acts as a fertilizer, and cattle can graze contentedly. Then the soil peters out, the number of cattle it can support drops by a factor of ten, and the farmer is desperate again. Meanwhile, the checkerboard remnants of forest may be too small to support biodiversity, or the isolated colonies of animals start inbreeding and eventually die off.

How to save Brazil's Atlantic rain forest from cash-strapped cocoa farmers? There is no simple solution, obviously. But Conservation International's man in Brazil, Gustavo Fonseca, is a fairly complicated guy. A world expert on primates, Fonseca is a workaholic with the demeanor of someone who has stayed up too many nights and smoked too many cigarettes. He can stroll through a forest and sense the presence of an animal that no one else can detect, and he can arrange a lengthy intimate dinner with President Fernando Henrique Cardoso of Brazil for Seligmann and Moore on short notice.

On the cocoa-rain forest problem, Fonseca demonstrated to officials of the northeastern coastal state of Bahia that their economy depended more on tourists than on cattle, thus enlisting their support. He approached the owners of Comandatuba, a posh five-star seaside hotel near the city of Ilheus, and calculated that if they could make the rain forest more attractive to tourists, the tourists would stay longer and spend more money. That gave the thousand people working at the hotel, and their families, a financial incentive to support the forest. He got the hotel, and Anheuser-Busch, which was mounting a big effort to sell Budweiser in Brazil, to help build a 60-foot-high canopied walk through the nearby rain forest, so tourists could ooh and aah. Fonseca informally approached big candymakers like Mars and Nestle and asked them to spend extra to buy "biodiversity-friendly" cocoa beans. He and a local environmental group organized small cocoa growers into something like a cooperative, so they could get a better price for their beans. Lately, Fonseca has been studying what other crops farmers can grow alongside their cocoa so they can afford to leave the forest intact.

CI has done similarly elaborate work elsewhere. When Mobil discovered oil near a hot spot in the Peruvian Andes, CI developed a set of guidelines for oil companies operating in environmentally sensitive areas. Among the recommendations: Don't build a service road along the pipeline, since that makes it easier for settlers to stream into the area. Seligmann says Mobil has been very cooperative.

All of which delights Gordon Moore, who describes Fonseca, and Conservation International, as "pragmatic and not doctrinaire." But it is not enough. The problem, says Moore, is that conservation groups, even CI, can rarely spot threats to biodiversity until they are enormous and difficult to reverse. Those Southeast Asian timber companies quietly snapped up rights to harvest a quarter of Suriname's virgin forests and were already cutting down trees before outsiders knew. How could all the conservationists, botanists, biologists, primatologists, and lepidopterists camped out in colleges and research stations all over the world miss something so big until it was almost too late? The fault, says Moore, lies in a common problem with scientific research, called reductionism. Scientists typically carve off a tiny sliver of a vastly complex matter and study it in minute detail. Narrowing the field of inquiry produces good science with reproducible, testable results. But unfortunately, he says, "the reductionist approach rarely creates an incentive for researchers to step back and take in the big picture." Environmental organizations, even CI, aren't blameless either, he notes. "Intellectually, conservation groups know they should cooperate. They all know they should share information and resources more. But in reality they all want to get all the credit."

That $35 million gift for a biodiversity research center, Moore hopes, will change that. If it works properly, the center will serve as a big-picture "distant early-warning center" to spot environmental threats and come up with ways to defuse them. He chose Fonseca to head the center because, he says, "Gustavo has done a superb job. He has changed attitudes about the environment in Brazil."

Fonseca and Moore admit they don't know exactly how anyone goes about setting up an environmental early-warning system. Fonseca says they expect to monitor commodity prices so as to know when farmers around the world might be getting desperate. They will study water quality for signs of industrial waste. They will keep track of large animals at the top of an ecosystem's food chain: When big animals disappear, that can mean that hunters are invading a region or that smaller animals are dying off. Fonseca has begun collecting aerial photos of hot spots and wants to hire experts in satellite imagery who can spot deforestation or new roads that may portend trouble. Not least, he and Moore want to establish communications links with research outposts around the world, including those run by other groups. "There are people out doing very focused studies on all kinds of subjects," says Fonseca. "At the same time, just by being there, they are observing an enormous amount of other information that is never collected and organized." Finally, Moore wants the center to develop yardsticks that can be used by organizations around the world to measure progress in preserving biodiversity. Seligmann says he doesn't know what such a yardstick might be, but admits he will be very relieved when he finds one. "Gordon is always after me on that. He keeps asking, 'What's the metric? How do we know if we're accomplishing anything?' " Who knows? Maybe there's room here for another Moore's law.

Intense conversations don't last long in the Pantanal, though. There are too many distractions. Fishing, of course. It can be too hot to talk. A magnificent, huge blue bird, the rare hyacinth macaw, may flap by, bringing conversation to a halt. A pitcherful of cold caiparinhas, the seductively paralyzing Brazilian concoction made of sugar-cane brandy, sugar, and lime juice, can induce a pleasant stupor in anyone. "My God, these are good," exclaims Gordon at one point, as though he'd never had one before. "Much better than daiquiris!"

At some point, the radiotelephone rings at the rustic and remote Pantanal ranch where we are staying. One of the richest and most powerful bankers in Brazil, Aloisio Faria, wants to meet with Seligmann and Moore. His son-in-law had met Moore at a cocktail party in Rio a few days earlier and had come away convinced that Faria should talk to them. He will send his helicopter to pick us up at the airport in Sao Paolo, and fly us on to Rio afterwards. Seligmann and Fonseca are ecstatic. They have been trying to meet with him for months. The two confer, agreeing to ask Faria for help in changing Brazil's tax laws so contributors to environmental causes get tax breaks.

Moore, who is not wearing his hearing aids, finally gets wind of what's going on. "So, we have a meeting, eh?" he says. Seligmann explains. It will add hours to the trip back to Rio, where Moore must catch an 11 P.M. plane back to the U.S. "Sure, I'll do it," he says, and adds with a mischievous grin, "as long as I don't have to wear a necktie."