Laura Dassow Walls's definitive biography, Henry David Thoreau: A Life, is an amazing achievement, a merger of comprehensiveness in content with pleasure in reading, following Thoreau’s progress as a writer and also as a reader, as well as his social and political involvements and scientific pursuits. Walls discusses Thoreau's legacy and why he still matters today.

Thoreau, we hear, was a hermit in the woods. What a ticket to irrelevance: who, in our Facebook age, can approve such selfishness, such misanthropy? But we labor, as Thoreau warned, under a mistake. As detailed in Henry David Thoreau: A Life, Walden Pond was just a few minutes’ walk from the center of town, where he went often to help with chores and join his family for dinner. Is this hypocrisy? Only to shallow purists; Thoreau met a few and mocked them, which, since they were often men with power, didn’t help his cause. As for him: he was a sworn realist. He had to be: Thoreau was born into a family of French immigrants and Yankee tradesmen just scraping by. His mother made ends meet by running their communal home as a boarding house, and the family scrimped to send him to Harvard—the scholarship boy, derided because he couldn’t afford a proper coat. The Thoreaus prospered only after Henry applied his Harvard education to his father’s pencil business, inventing both a better pencil and the machinery to make it. To keep it all afloat took hard work and Yankee thrift.

Yet there was something strange about Henry, a restless, fierce desire to see into the heart of the cosmos. Even as he relished good conversation, he guarded the solitude he needed for creative life, a tension that drove his creative process. He’d gone to Walden with his life in crisis, having veered from one dead end to another until the only option left was the crazy dream he’d cherished since childhood: to go away and live by the pond, and write his way through the changing seasons. For two years, from July 1845 to September 1847, he followed that dream faithfully. For the rest of his life, he lived in large and bustling households, earning a living as a pencil-maker and land surveyor, walking, traveling, lecturing—and, not incidentally, authoring a stack of books that put him among the world’s great writers. So: does he have anything to say to us?

1. Why go to Walden Pond? Thoreau went to Walden to think deeply about a world in which he feared thinking no longer had a place. “I went to the woods because I wished to live deliberately,” he tells us: the human capacity to deliberate—to weigh our life choices consciously rather than go with the flow of our habits and prejudices—asserts a freedom we’ve forgotten we have. The first step is to identify the rock-bottom essentials. What is it you simply cannot live without? “Simplify, simplify,” he pleads. Keeping it simple makes both our mistakes and our desires easier to see. Thoreau identified our mistakes cuttingly enough: we surrender to an economy that lures us into mindless consumerism. He also identified his true desire: to become a serious writer, with a unique voice and an original stance. At Walden he drafted two books and three major essays, turning his life around.

2. But why leave Walden? Thoreau doesn’t tell us the real reason: because Emerson’s wife asked him to live with her while the great man was lecturing abroad. That is, he left to do his friends a favor. But he admits he was ready to leave: ironically, his life of escaping ruts had itself become a rut. It was time to shake loose. Even though changing his address hadn’t much changed his relationships with friends and family, moving back to town did made a big difference, for it put everything he’d learned at Walden to the test. If it were real, he wouldn’t leave Walden behind so much as bring it along. That is, the solution lay not in where he lived, but how. Walden is not a place but a philosophy: living deliberately turns out to be portable.

3. Sometimes Walden isn’t where you need to be. In 1854, when Walden was in press, Thoreau learned that Anthony Burns, a fugitive slave living in Boston, had been captured and remanded to slavery. As protests veered into violence, the author of “Civil Disobedience” questioned his deepest faith. “I walk toward one of our ponds,” he asked, “but what signifies the beauty of nature when men are base?”—asked while standing on a stage, facing hundreds gathered at an angry political rally, and treading on the ashes of the U.S. Constitution which William Lloyd Garrison had just burned in protest. “Slavery in Massachusetts” was a scorching indictment of his neighbor’s complicity with Southern slavery. Sometimes one walks not to Walden but to a public stage, to offer, without flinching, one’s most searching deliberations to the world.

4. Because politics is big, but the cosmos is bigger. Thoreau worried about his own complicity with injustice, too. As he asked himself following Burns’ arrest, “Is our life innocent enough? Do we live inhumanely—toward man or best—in thought or act?” Thoreau had good company in his antislavery thinking, but when he extended civil rights to the natural world, he stood virtually alone. “Who hears the fishes when they cry?,” he challenges us, while speculating what a crow-bar might do against the dams that destroyed them. After witnessing the clearcutting of Maine’s forests, he asserted that trees have souls, in a passage deemed so outrageous that his editor censored it. No bright line divides social justice from natural justice; sometimes Walden is exactly where you need to go, because that’s where you can see how political injustice and environmental depredation share a common cause.

5. Beware of losing the commons. Emerson, dripping contempt, called Thoreau “the captain of a huckleberry party” who should have “engineered for America.” But that’s just what Thoreau thought he was doing, by leading neighborhood children on berry-picking parties. Stewardship of the land meant recognizing nature as a commons, and everywhere he looked, as woods were felled for profit and hilltops were engulfed by housing projects, Thoreau saw the commons under threat. He was furious when he found his favorite huckleberry patches fenced off with “No Trespassing” signs. In response he called on the town to protect its natural features “as a common possession forever,” for their beauty, but also for their educational value. That is, stewardship meant defending the community’s spaces of knowledge, inquiry, and discussion as well—town meetings and public schools, libraries and reading rooms, the Lyceum where he lectured regularly. “It is time that villages were universities,” he insists, where all men and women can get a lifelong liberal education—uncommon schools worthy of America.

6. Some places shouldn’t be common, but wild. Thoreau’s manifesto is eight words long: “In Wildness is the preservation of the world.” He found wildness on faraway mountaintops, but also in the heart of a swamp a few minutes’ walk from home, and in the woods of Walden, too, even after they’d been farmed, logged, and abused for generations. Wildness meant “willed,” self-willed, untrammeled by human control and appropriation. Knowledge, too, is wild: not cut and stacked like cordwood, but a flash of insight, a spark connecting mind and world, “the lighting up of the mist by the sun.”

7. The same is true of people. Thoreau believed that true democracy could tolerate a few souls who, like himself, lived independent lives—democracy’s “wild fruits.” He was painfully aware of his differences: his resistance to convention, his unyielding need for solitude, his profound love for all wild beings, his shyness and inability to make small talk, his sexual confusion and unnamable longings, his compulsion to write. Critics call him a misfit, though friends love him deeply. Is Thoreau a pain and a braggart? Of course. But as he said of Walt Whitman, in whom he recognized a fellow-spirit: there are a few who earn that right.