The new biography “Henry David Thoreau: A Life” is the masterpiece that the gadfly of youthful America deserves. I have been reading Thoreau and reading about him for 40 years; I’ve written a book about him myself. Yet often I responded to Laura Dassow Walls’s compelling narrative with mutterings such as “I never knew that” and “I hadn’t thought of it that way.” I found myself caught up in these New England lives all over again.

(University Of Chicago Press)

On a foundation of rigorous scholarship, Walls, a professor of English at Notre Dame, resurrects Thoreau’s life with a novelist’s sympathy and pacing. Most of her previous books are about either the American Transcendentalists or the explorer and naturalist Alexander von Humboldt, and her broad grasp of the era’s scientific issues integrates Thoreau’s dawning ecological conscience into a better-understood context than most writers on the topic can provide.

Every biographer faces the challenge of portraying and deciphering a subject’s parents — their history, their mythic resonance throughout the subject’s life. Walls does both with aplomb. “John Thoreau would be remembered as a quiet man,” she writes of Henry’s father, “unambitious and too decent to press the hard bargains needed for success in the cash-poor early republic. But time and again, he met defeat by taking a forward leap, such as opening his own store, and when it failed, trying again in Maine.” Walls builds up John’s character scene by scene, and when he dies, I felt deeply sad despite knowing this story well.

Henry’s mother, a huge influence on her son and a woman whom many friends and neighbors memorialized, comes alive in this biography. “If few noticed John,” Walls writes, “everyone noticed the indomitable Cynthia, who stood a head taller than her husband and was one of the most famous talkers of the day, full of wit and anecdote spiced with sarcasm, and blessed with that brisk efficiency that New Englanders call ‘faculty.’ ” She remains a strong and witty presence throughout.

Both of Henry’s smart and resourceful sisters, Helen and Sophia, influenced him — not least as informed and passionate abolitionists, encouraging his activism. But no person in his life affected him more than his handsome older brother, John Jr., whom he adored. Henry imitated him in hobbies, romance and even — after John died of tetanus in Henry’s arms — in medical symptoms. John’s death resulted in Henry’s breakdown, out of which he climbed with difficulty.

(University of Chicago Press/Author Laura Dassow Walls )

Thoreau’s era is fascinating for many reasons, including the Transcendentalist reassessments of religion and society during the 1840s, the bloody results of the Fugitive Slave Act of 1850, the war with Mexico between 1846 and 1848, and the start of the Civil War, which was still raging when Thoreau died in 1862. Far from hiding out in the woods, Thoreau was passionately involved in these issues. His now-famous night in jail was an orchestrated public protest; he supported the violent abolitionist John Brown. Decades later, both Gandhi and Martin Luther King Jr. credited Thoreau’s essay “Civil Disobedience” with helping inspire their own nonviolent activism.

Walls is too well versed in Thoreau’s life to accept his own often contradictory pronouncements or his semi-fictional first-person narrator as necessarily factual. She teases out nuances and implications, but without unfounded speculation. And often she sums up a trait with a sly image, such as the final clause of this sentence: “Moving to Walden Pond thus had a double purpose: it offered a writer’s retreat, where Thoreau could follow his calling as spiritual seeker, philosopher, and poet; and it offered a public stage on which he could dramatize his one-person revolution in consciousness, making his protest a form of performance art.”

Thoreau was preoccupied with natural rhythms: day and night, summer and winter, seed and harvest. He celebrated their parade and exploited their symbolism. In Walls’s later pages, as Thoreau battles tuberculosis and slips toward death at the age of 44, she aptly employs his own imagery: “As the days shortened and the leaves fell, a new Thoreau emerged: pensive and sadder, slower, deeper. As he fought to regain strength, fighting the grave, he turned to the most common activities and the most mundane needs with intentionality and deliberation. Walden had been his book of spring and summer. Now, willing his recovery, he was learning a mind of autumn. In these darkening and haunted pages of his Journal, Thoreau began to trace the outlines of Walden’s sequel: he would call it Wild Fruits, and it would be his final harvest.”

Michael Sims’s recent books include “Arthur and Sherlock” and “The Adventures of Henry Thoreau.”

This week, Michael Dirda’s review will appear on Sunday in Arts & Style.

Henry David Thoreau
A Life

By Laura Dassow Walls

University of Chicago Press. 615 pp. $35