Eliza Griswold is a senior fellow at the New America Foundation and the recipient of a Guggenheim fellowship: “On June 4, 1963, less than a year after the controversial environmental classic “Silent Spring” was published, its author, Rachel Carson, testified before a Senate subcommittee on pesticides. She was 56 and dying of breast cancer. She told almost no one…“Every once in a while in the history of mankind, a book has appeared which has substantially altered the course of history,” Senator Ernest Gruen­ing, a Democrat from Alaska, told Carson at the time. “Silent Spring” was published 50 years ago this month. Though she did not set out to do so, Carson influenced the environmental movement as no one had since the 19th century’s most celebrated hermit, Henry David Thoreau, wrote about Walden Pond. “Silent Spring” presents a view of nature compromised by synthetic pesticides, especially DDT. Once these pesticides entered the biosphere, Carson argued, they not only killed bugs but also made their way up the food chain to threaten bird and fish populations and could eventually sicken children. Much of the data and case studies that Carson drew from weren’t new; the scientific community had known of these findings for some time, but Carson was the first to put them all together for the general public and to draw stark and far-reaching conclusions. In doing so, Carson, the citizen-scientist, spawned a revolution. “Silent Spring,” which has sold more than two million copies, made a powerful case for the idea that if humankind poisoned nature, nature would in turn poison humankind. “Our heedless and destructive acts enter into the vast cycles of the earth and in time return to bring hazard to ourselves,” she told the subcommittee. We still see the effects of unfettered human intervention through Carson’s eyes: she popularized modern ecology.”