Henry David Thoreau was born in 1817 in Concord, Massachusetts, as David Henry Thoreau — he swapped the names in 1837, when he started keeping a journal. Raised in a modest New England family, Thoreau studied at Harvard University but returned to Concord after graduation. He had no set career path, briefly teaching, working at his father’s pencil factory, and even starting a small progressive school in 1838. When his brother died three years later, Thoreau closed the school and returned to work at the pencil factory; at around the same time, his friend and mentor, fellow Concordian Ralph Waldo Emerson, invited him to live as a handyman at his home.

By this time, Emerson was a well-respected writer and philosopher. Thoreau’s own outlook was shaped by Emerson’s transcendentalism, a philosophy and literary movement emphasizing nature and individual intuition. With his mentor’s help, Thoreau had writing published in the transcendentalist publication The Dial and himself became a leading figure in the movement. Eventually, Thoreau built a place of his own on a piece of Emerson’s land near Walden Pond. There, he embarked on his famed experiment of simple living, a retreat between the years of 1845 and 1847 that led to his seminal work Walden (1854). The book, a reflection on living slowly and deliberately among nature, enjoyed modest success at the time, but went on to become a cornerstone of American naturalist literature.

Thoreau’s time at Walden Pond wasn’t entirely idyllic: In 1846, after refusing to pay a poll tax in protest against slavery and the Mexican-American War, Thoreau spent a night in jail; his resulting essay “Resistance to Civil Government” (later known as “Civil Disobedience”) established him as an outspoken nonconformist. He was also a dedicated abolitionist, participating in the Underground Railroad and speaking out against federal slavery laws. Thoreau’s travels were provincial — to Maine, Canada, Cape Cod, and later, Minnesota — but impactful on his nature writing, as were his daily walks in Concord, immortalized in his famous lecture-turned-essay, “Walking.” Thoreau died in 1862 at age 44.