WASHINGTON — Here, in a study that faces the garden, is where Rachel Carson would sit and write on days when she felt well.

WASHINGTON — Here, in a study that faces the garden, is where Rachel Carson would sit and write on days when she felt well.

Here, in a bedroom with a dogwood outside the window, is where she would lie down and write on days when she felt worse.

On her sickest days, as Carson struggled with cancer and radiation therapy, she came back to her brick house in Silver Spring, Md., and couldn't write at all. Instead, an assistant read her words back to her, allowing her to edit even when she couldn't sit up.

"She had such a sense of responsibility, that it was all on her. It had to succeed,'' said environmental activist Diana Post, giving a tour of the house this week.

Carson's book "Silent Spring,'' published in 1962, led to the banning of the pesticide DDT, the launch of modern environmentalism and her enshrinement as a kind of patron saint of nature. In this region, Carson's name has been given to two schools, a park and a hiking trail — and it is evoked seemingly whenever environmentalists gather.

But this year, as the 100th anniversary of her birth approaches, people are also remembering the personal story that goes with Carson's legend. She was a former government press-release writer who captivated official Washington. Her public victory came at crushing private costs.

"She could not live with herself if she didn't speak out,'' said Post, president of an educational group, the Rachel Carson Council Inc., now run out of the Silver Spring house. The house is open to the public by appointment.

This weekend, events honoring Carson will include a 23-mile hike on the route of the planned Rachel Carson Greenway in Montgomery County, Md., an open house at her former home and a ceremony at the National Wildlife Visitor Center in Laurel, Md.

Commemorations are also planned at Rachel Carson Elementary School in Gaithersburg, Md., and Rachel Carson Middle School in Herndon, Va. Carson's 100th birthday would have been May 27.

Forty-three years after her death, Carson is still cited as an inspiration across the environmental spectrum, by endangered-species advocates and anti-pesticide groups and researchers concerned about hormone-mimicking pollutants.

Mark Lytle, a professor at Bard College in Annandale-on-Hudson, N.Y., said that all of these movements can be traced in some way to Carson and her call to look more closely at humans' destruction of natural systems.

This importance stands in sharp contrast with the humble way that Carson arrived in Washington.

In 1935, with a master's degree in zoology from Johns Hopkins University, the Pennsylvania native was hired as a government contractor to write scripts for a radio nature show, "Romance Under the Waters.'' She made $6.50 a day. In 1936, Carson became a full-time science writer, and she stayed with the government for 16 more years. Carson also raised a grand-nephew, Roger Christie, whom she adopted as a son.

These were less cautious times in wildlife management: Government officials were still handing out recipes for eating the animals they studied. Still, in 1945, the U.S. Fish and Wildlife Service was conducting research on a widely used pesticide.

"DDT may have undesirable and even dangerous effects unless its use is properly controlled,'' said a news release, which Carson helped write.

"It stuck in the back of her mind, apparently,'' said Mark Madison, a historian for the Fish and Wildlife Service, Carson's employer for much of her career.

In the late 1950s, after Carson had written mega-selling books about life in the ocean and made enough money to retire from the government, she came back to the subject of DDT.

New studies had shown that the chemical, sprayed broadly to kill mosquitoes and other pests, could hamper the reproduction of birds. She found additional evidence that man-made chemicals were harming fish and other wildlife as well as indications that they could be causing cancer in humans.

Then, in the midst of working on the book, Carson discovered that she had cancer — tumors that began in her breast and eventually spread through her body.

As she fought the disease, being shuttled to a Washington hospital for treatment, Carson had decided she could tell almost no one about her condition.

"She realized even before the book was published that if the chemical industry ... understood that she had cancer, they would have another potent, personal way to refute what she wrote,'' said Linda Lear, a George Washington University research professor who wrote a biography of Carson published in 1997.

Lear said Carson wanted people to know that her book — which she wrote in Silver Spring and at a home in Maine — was based on sound science, not anger over her illness.

Carson continued to hide her disease after the book was published. Signs of her illness were blamed on arthritis or the flu. When she appeared on "CBS Reports,'' she wore a dark wig.

"You never saw me look better. Please say that,'' Carson wrote to a friend, telling her what to say when people inquired about Carson's health, according to a letter quoted by Lear.

The cost of this approach was that Carson fought her disease nearly alone. Her cancer was still a surprise to many people when she died at the house in Silver Spring in 1964, at age 56.

In the years since her death, Carson's conclusions about DDT have remained controversial. This year, during a hearing meant to honor Carson in Annapolis, Md., state Sen. Andrew Harris said her book had helped scare people away from a pesticide that could have saved numerous human lives.

"In the end, you know, people are dying of malaria that don't need to die'' because of bans on DDT, Harris, a doctor, said in an interview this week.

But the impact of her message was astounding. In the decade after her death, the U.S. government enacted a string of environmental laws, created the Environmental Protection Agency and banned most uses of DDT.

Outside Washington, Carson's book altered the nature of environmentalism. Previously, it had been mainly about preserving and appreciating parks and other beautiful places. But Carson's message was that all of nature should be protected, for its own sake and because people eventually would suffer if it was degraded.

"What she said was, the Earth itself needs an advocate,'' said Patricia DeMarco, executive director of the Rachel Carson Homestead Association, which runs an educational center at her childhood home, in Springdale, Pa.

Since then, Carson's message has been taken up by a profusion of new and newly aggressive environmental groups. Perhaps the most concrete gauge of the book's continuing relevance is that it still sells: 150,000 copies in the past five years, remarkable for a book 45 years old.

Lear, her biographer, said Carson felt that her struggle had paid off.

By the time she died, Lear said, the story was out.

"She had said what she felt she had to say before she died,'' Lear said. Still, "there was a lot more that she wanted to say.''