This week marks Henry David Thoreau’s 200th birthday, a bicentennial that emphasizes just how briefly the writer lived. He died before he was 45, but “Walden” is immortal.

Henry David Thoreau (1817 – 1862) (Getty Images/iStockphoto)

“I went to the woods because I wished to live deliberately,” Thoreau writes, “to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived.”

Except for a couple of more explicitly religious works, “Walden” is my favorite book, one I’d want with me on a desert island surrounded by pond water. I also might haul along my cherished copy of Thoreau’s journal, a giant two-volume edition of a 14-volume version. (No, it’s not abridged; this feat of compression is accomplished by reproducing four small pages on each leaf. And there’s no index, which encourages happy wandering.) I bought the set at a bookstore in Concord, Mass., decades ago for $60 cash — remembering Thoreau’s warning that “the cost of a thing is the amount of what I will call life which is required to be exchanged for it, immediately or in the long run.” I’ve never regretted it.

As a teenager, “Walden” electrified me, giving voice to my febrile self-righteousness. Raised on the Gospels and the metaphysical aphorisms of Mary Baker Eddy, I regarded Thoreau’s book as a loamy version of “Science and Health.” I swear, it seemed to glow every time I reached that last climactic paragraph: “Only that day dawns to which we are awake. There is more day to dawn. The sun is but a morning star.”

Thoreau’s zealous rejection of conventionality is especially designed for young misfits who hear a different drummer. His transcendental sentences encourage people struggling to reconceive the oppressive order of the world in a way that lets them imagine they’re above it all. As I grew older, though, I began to understand that Thoreau’s claim that “the mass of men lead lives of quiet desperation” was not social criticism but personal confession.

A replica of Thoreau’s cabin in Walden Woods, Concord, Mass. (Getty Images/iStockphoto)

As a high school teacher and college professor, I read “Walden” with my students again and again. Many of them thought it was a slog, though I suspect some of them weren’t actually reading it (suggesting that even the SparkNotes were a slog). For a few of these years, I was teaching at the John Burroughs School in St. Louis, the same school where a future star named Jon Hamm was teaching drama, so the competition for ardor was fairly intense. Some students felt Thoreau sounded arrogant. Others were disgusted — as only young people can be — that Thoreau misrepresented himself and his time in the cabin. (He had far more company than he describes; he sometimes went home for meals; etc.)

But every year, two or three of my students caught fire reading “Walden.” Ignoring the autobiographical elisions, they resonated to the book’s insistence that we mustn’t settle for the spirit-sapping path society has laid out for us. I saw these young people copying into their journals the same rousing passages I had once copied into mine:

“If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.”

“If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them.”

I’m a lot closer to retirement than graduation, but those lines still strike me as revelations.

This month, Thoreau is the subject of a major new biography by Laura Dassow Walls. Our reviewer, Michael Sims, calls her book a “masterpiece that the gadfly of youthful America deserves.” (My own knowledge of Thoreau’s life is based on Robert Richardson’s 1986 biography “Henry Thoreau: A Life of the Mind.”)

I haven’t reread “Walden” in over a decade, but news of this new biography makes me realize that it’s time I went back to the woods, deliberately.

Ron Charles is the editor of Book World.