You can see why the pharaohs of Egypt revered cheetahs, why they fascinated William the Conqueror and why Kublai Khan supposedly kept a thousand of them for hunting. Nothing in this world—absolutely nothing—moves like a cheetah. The sprint is their trademark—they run down kudu antelope on the African plain, zero to 70 in four seconds, 25 feet per stride, oversize heart going like a train, nostrils flared in the bullet skull. The kudus don't stand a chance.

Or watch them lope effortlessly alongside a truck going 25 miles an hour, waiting for gamekeepers to toss them five-pound chunks of giraffe meat. They glide soundlessly, unblinking amber eyes focused only on dinner. Listen as they chase a rag flicked like a fishing lure back and forth in the high grass. They pivot like dancers, ropy tails twirling for balance as the cat feet tremble the earth like jackhammers. Cheetahs weigh between 75 and 120 pounds, but their whippy torsos are nothing more than stripped-down chassis for fabulous legs. Nothing out-quicks a cheetah.

"We run them as much as we can," says Laurie Marker, striding back and forth, trailing the lure in the front yard of her ranch house about 30 miles east of Otjiwarongo, in northern Namibia, while Kanini, a 1-year-old orphan female, pounces and leaps in her wake. "They need the exercise."

Kanini, whose name means "Little One" in the Namibian language of Oshivambo, stops chasing the lure. She jogs regally back and forth between Marker and me, rubbing against our trousers and clamoring for attention, her purr gurgling like an idling Ferrari. Her beautiful coat feels like AstroTurf; it is an incongruity in what otherwise seems a perfect creature, but it is probably a blessing. Thanks to its rough texture, there is little market for cheetah fur.

Marker, striking at 54, probably knows more about cheetahs than anyone alive. She tracks them, tags them, knocks them out and samples their blood, checks their poop to see what they eat and provides guard dogs to Namibian farmers and ranchers to keep them away from livestock. She also takes her work home with her. When David Wildt, a biologist at the National Zoo in Washington, D.C., first met her 30 years ago, the only thing he knew about her was that she slept with a cheetah named Khayam curled next to her bed. "That really impressed me," he says.

Today Marker is executive director of the Cheetah Conservation Fund, a million-dollar-a-year nonprofit foundation she built from scratch that has become the template for a new, visionary approach to wildlife management. Without her, the fleet-footed predators of Africa's bush country would likely be closer to extinction. Even now they are not safe, for despite their elegant history and their acrobatic grace, they are flawed creatures. They have a low fertility rate, a high incidence of birth defects and weak immune systems. And by hunting them unmercifully for most of the past century, humans reduced their numbers from about 100,000 worldwide in 1900 to about 30,000 in the 1970s. That's when Marker stepped in.

Laurie Marker was raised in a suburb of Los Angeles, where her father, trained as an agricultural economist, worked in the aerospace industry and kept horses, rabbits and other animals in the backyard. Marker went to San Francisco State University to study psychology, then transferred to Napa Valley College to learn winemaking. She left college in 1972 to start a vineyard with her husband and two other couples in Winston, Oregon. To help bankroll the venture, Marker, barely 20, worked at an animal park called Wildlife Safari.

The sum total of what was then known about cheetahs at Wildlife Safari was that they were fascinating, standoffish and virtually impossible to breed. The cheetahs had been isolated on a hilltop away from visitors in hopes they would mate. Captivated, Marker started to ask questions, read books and conduct research about the animals. "I plod," she says. "But I'm a finisher." (In 2002, at 48, she earned a PhD from Oxford University. Her dissertation, Aspects of Cheetah [Acinonyx jubatus] Biology, Ecology and Conservation Strategies on Namibian Farmlands, is considered the last word on cheetahs.)

But in the 1970s cheetahs were still a riddle. They were easily domesticated and long revered—King Tut's tomb was decorated with several cheetah statues, and rulers since ancient times had kept them as pets and used them as hunting companions. Yet history had recorded only one litter born in captivity—in the stables of the 16th-century Indian Mughal emperor Jahangir—before the birth of three cubs at the Philadelphia Zoo in 1956, all of which died within three months. The failure of captive breeding meant that cheetah fanciers had to replenish their supply with wild ones. "For thousands of years, we've been loving them to extinction," Marker says. Cheetahs once ranged across south Asia, the Middle East and Africa, but by the late 1970s, they were gone from Asia, except for a few in Iran, and were declining rapidly in Africa, where ranchers routinely shot them to keep them away from livestock. With the animals facing oblivion, scientists got busy.

Starting in 1980, researchers affiliated with the National Zoo began to examine the cheetah's reproductive characteristics and conduct the first-ever studies of cheetah DNA. The zoo sent a research team to South Africa to obtain semen and blood samples from about 80 cheetahs at a refuge. Wildt, then a reproductive biologist at the National Institutes of Health (NIH), was studying cat biology. He examined the semen under a microscope and found shockingly low sperm counts—about 10 percent of the norm for other felines. And there were huge numbers of malformed sperm—about 70 percent in each sample. This explained the animals' low fertility.

The blood samples went to Stephen O'Brien at NIH. He had studied the domestic cat as a model for human viral cancers and was interested in genetic variation. In most cat species, enzymes in the blood differ genetically between individuals by 20 percent to 50 percent. But the cheetahs' blood enzymes were all alike. "We found nothing," says O'Brien, no variation at all. After looking at 52 genes, O'Brien halted the study. The cheetahs were virtual clones.

Were they catastrophically inbred? To test that hypothesis, O'Brien and Wildt needed more samples. Zookeepers had made great strides in breeding cheetahs since the three cubs died in Philadelphia, but Wildlife Safari—with Marker in charge of the cheetahs—had the most successful breeding operation in the country, with three dozen animals on hand. It would successfully raise more than 100 cheetah cubs during the 16 years Marker worked there.

In Oregon, Wildt and O'Brien took skin samples from eight Wildlife Safari cheetahs and grafted them onto other cheetahs. Ordinarily, as in human transplants, a host will reject a donor organ unless there is a close tissue match and an assist from immunosuppressant drugs. But the cheetah grafts were accepted in every case. This was disturbing news, for it meant that their immune systems were so similar that almost every cheetah in the world had the same vulnerability to the same diseases. In fact, in 1982, Wildlife Safari lost 60 percent of its cheetahs to an epidemic of viral peritonitis. "It went through the center like wildfire," Marker says. The same disease in any genetically diverse cat population could be expected to kill 2 percent to 5 percent of its victims.

Where had the cheetah gone wrong? By analyzing the few variations in cheetah DNA, O'Brien and Wildt determined that cheetahs had passed through a population "bottleneck" about 12,000 years ago. Some apocalyptic event had wiped out all but a few animals that then interbred, with disastrous consequences for the animal's gene pool. The obvious culprit was the onset of the last ice age, a cold snap that coincided with the extinction of saber-toothed cats, mastodons and other large prehistoric mammals. Fossil evidence shows that cheetahs evolved in North America about 8.5 million years ago and then spread throughout Asia, India, Europe and Africa; the modern species appeared about 200,000 years ago. The bottleneck wiped out all of North America's animals.

Wildt, O'Brien and Marker's National Zoo-led studies have informed everything that has happened in cheetah management and conservation since the 1980s. Researchers now know that the cheetah will not be a robust, vigorous species anytime in the foreseeable future and that saving the animals, Marker's proclaimed goal, thus requires a combination of strategies. Protecting and studying them in the wild is one approach, while at the same time scientists are refining techniques to breed them in captivity, hoping to build what Wildt calls an insurance policy for the wild population. The work continues today at the new Cheetah Science Facility in Front Royal, Virginia.

Marker, by then divorced, moved to Washington in 1988 to run the National Zoo's program to broaden genetic analysis in breeding cheetahs and other animals. She spent three years there before shedding her worldly goods and moving to Namibia. She sold what she could—including her mobile home in Oregon—gave away most of the rest and departed with $15,000.

"I thought if I told enough people about the threat to cheetahs, they would take care of it, but they never did," Marker says. "[People] were always saying, ‘somebody ought to do something about cheetahs,' but I could never find out who ‘somebody' was. So I went."

Marker arrived in namibia at a watershed moment. Colonized by Germany in the 19th century and annexed by apartheid South Africa after World War I, the country known as South West Africa became an international cause in the 1960s as the guerrilla South West Africa People's Organization (SWAPO) fought to end colonialism. In 1988, South Africa agreed to vacate Namibia, and the country gained independence in March 1990. Marker arrived April 1, 1991. "At first there was a lot of standoffishness, especially among the white folks," she recalls. "I was a U.S. citizen, and we had supported SWAPO, which, as far as they were concerned, was the wrong side."

With two million people living in an area nearly twice the size of California, Namibia is one of the least populated countries on earth; a motorist can drive 100 miles without seeing more than a half-dozen people. And the countryside teems with wildlife. Troops of jeering baboons greet motorists along the highway leading north from Windhoek, the capital. Families of wart hogs snuffle through the underbrush, and bushy-tailed jackals lurk in the grass. At water holes even a casual visitor can be confident of seeing a suite of marvelous creatures—eland, kudu, oryx, hartebeest. In all, Namibia boasts more than 20 species of antelope.

The cheetah is a top-of-the-line predator on the high plains. But, as Marker notes, cheetahs are one-trick cats. They can run down and kill anything their own size, or considerably bigger if they hunt together, but their legendary burst of speed—up to 70 miles per hour—is good for only about a quarter of a mile, and the chase leaves them badly winded and vulnerable. Bigger, nastier opportunists—lions, leopards and hyenas—frequently steal cheetah kills and, for good measure, then kill the exhausted cheetah's young.

Females define the cheetahs' unusual social order. Except when raising cubs, they are loners, and they select their mating partners. Males, meanwhile, form coalitions of siblings that hunt together and may remain together for life. In Namibia, males range over an area of about 860 square miles, while females travel farther—more than 1,500 square miles. Mothers have litters of up to six blind and helpless cubs. Perhaps to hide them from predators, cheetah mothers move their cubs to different dens every few days for the first six weeks of life (which makes tracking growing cubs difficult for researchers). Cheetah females reach maturity and leave the family when they are about 2 years old. No one knows for sure how long they survive in the wild; the animals live between 8 and 12 years in captivity.

In Namibia, 95 percent of cheetahs live on territory owned by ranchers. When Marker first got there, ranchers typically called cheetah "vermin" and killed about 600 every year. Marker's plan was simple. From the Windhoek airport, she traveled north in her Land Rover toward Otjiwarongo, "going door-to-door, talking to two farmers a day," she says, asking them how they managed their cattle herds, what they thought about the wildlife on their property and what problems they thought cheetahs were causing.

Marker shared her expertise as it grew. Cheetahs could not kill full-grown cattle, she explained, so ranchers might want to focus on protecting newborn calves. Cheetahs would rather eat wild game than risk an encounter with humans, she said, so instead of driving game away, ranchers should learn to live with it.

Her strategy emerged only gradually. "Here in Namibia we have wildlife, livestock and a unique ecosystem," Marker recalls telling the ranchers. "It is possible to make a living off every aspect of this, and you can have it all—if you have good livestock management. You can manage for predators, and you can make it work for profit."

By the time she had worked her way up to Harry Schneider-Waterberg's farm, she had filled notebooks with data. Schneider-Waterberg was in his mid-20s at the time, just starting to run the 104,000-acre farm that had been in his family for a century. "She told me that farmers with good management practices lost less livestock, and she had the facts to back it up," Schneider-Waterberg recalls. "I was young, just putting together my plan, and I thought if we can cut predator losses by doing these things, then I know where I'm going."

The best ranches, Marker told the ranchers, kept records for each animal, used herdsmen to spot cows ready to calve, then brought them into an enclosure until they did so. She explained that cheetahs won't come near donkeys, which can be extremely aggressive with other animals, including dogs, jackals and even leopards. She suggested using donkeys to guard cattle herds. "It was all information I could use," Schneider recalls, "never accusing." He now chairs the Waterberg Conservancy, a vast expanse of Namibian plains owned by 11 neighboring ranchers and the Cheetah Conservation Fund.

For the first few years, Marker camped in a succession of loaned farmhouses. In 1994, she bought the CCF property for $350,000 with grant money and a gift from a benefactor with ties to the Cincinnati Zoo. The property sprawls over 100,000 acres of savanna in the heart of cheetah country.

By that time, many of the ranchers had stopped killing cheetahs and were instead bringing those they had trapped to Marker, who took blood and semen samples from the animals, checked their age and health, and tagged and released them. Since 1991, Marker has done these work-ups on more than 800 cheetahs. She also established a sanctuary for motherless cubs; today it houses 46 orphans.

Marker's observations of cheetah behavior constitute most of what we know about them. She began fitting wild cheetahs with radio collars and following them with airplanes in 1992. She discovered that males, in groups, and females, which are solitary, roam over vast stretches of territory. Marker was the first to understand that females are the ones that select mates—a major reason why captive breeding had such a poor record: researchers had not known that it was ladies' choice, so giving single males a chance at several females—a standard breeding procedure—didn't work. She also learned that if two or more females occupy the same space, they may suppress each other's reproductive hormones. Today, breeders isolate females and let them choose mates from among the available males.

Marker also began integrated local education programs. There was not a lot of mixing between black and white students at first, Marker says, "but I polished up everybody's English. Soon the kids were all speaking American slang." Tribal leaders told her that the loss of even a single animal—cow, sheep or goat—to a marauding cheetah could cause great hardship. "If people are hungry," Marker says, "they could care less about conservation." In 1990, to help the African shepherds and goatherds, Marker consulted evolutionary biologist Ray Coppinger of Hampshire College, in Amherst, Massachusetts, who recommended she use guard dogs instead of donkeys, which are aggressive toward sheep and goats. Marker chose the Anatolian shepherd, from Turkey, a black-faced, cream-colored short-haired breed that weighs up to 130 pounds. In 1994 Coppinger brought four Anatolian adults and four pups to Namibia and helped Marker set up a breeding program. Over the years she has given away 280 puppies to ranches and communes all over the country.

Today Marker, who gets donations from around the world, supervises 13 full-time professionals and 25 support staffers. At any one time she may have a dozen or more visiting researchers, veterinarians and students on-site. She has scientific or educational ties to universities all over the world. At local high schools, her helpers teach kids about farm surveys and radio tracking, biomedicine and genetics, publicity and fund-raising. Under the aegis of the conservation agency Earthwatch, volunteers can take working vacations at the Fund, doing everything from fence-building to cheetah-feeding. Marker has powerful friends. Sam Nujoma, independent Namibia's first president, is the Fund's formally designated "patron," and Marker is currently the chair of the Conservancy Association of Namibia, the umbrella organization of Namibia's conservation-minded landowners. She also maintains an international cheetah studbook.

Marker, whose second marriage ended in 1996, now lives with Bruce Brewer, a former curator at Chicago's Brookfield Zoo. He manages most of the day-to-day affairs at the Fund, which has grown to include dormitories, a mess hall, classrooms, research facilities and labs, a guest house and a gift shop. Marker makes fund-raising trips each year to the United States, has a satellite program in Kenya, assists cheetah conservation efforts in Algeria and Iran, trains farmers in Botswana and breeds dogs in South Africa.

Today the world cheetah population stands at about 12,500 animals in 26 countries. "We are at the lowest point in probably 9,000 years," Marker says. But she's shown that conservation can work. Namibia's share—the world's largest—stabilized a few years ago at 3,000 and is increasing slightly. This is Marker's doing. "Laurie's major contribution has been turning around the rapid loss"

"Our approach is for the community to live with its wildlife," Marker says. "But you have to give them a reason." Many ranchers in Namibia's cheetah country now encourage tourists, researchers and other animal lovers to enjoy the wildlife. "Laurie saw the bigger picture," says rancher Schneider-Waterberg. "She was talking about how the whole world was going to know about the cheetahs. And it does."

Guy Gugliotta wrote about computerizing Old Bailey court records in the April 2007 issue of Smithsonian.

Wildlife photographer Suzi Eszterhas lives in San Rafael, California.