Half an hour from Cambridge is Walden Pond. In 1845, Henry David Thoreau '37 was the only human who knew its shores intimately; now, thousands of swimmers and small-time fishermen are acquainted with the rules (no inflatables) and price of admission (cash only; no checks).

On a recent Saturday afternoon, walkers outnumbered sun-worshipers. The part of the path connecting the beach to the clearing where Thoreau's cabin once stood was well-traveled; the pine needles and leaves on it had been ground into dust.

"Have you had the car tested?" a man in his twenties said to the older man in front of him.

"Last week," the man grunted. "It didn't pass."

"Something in the exhaust?" the younger one asked.

The man nodded. "God knows what," he said. "One of these days it'll turn out that all these emissions are actually good for the environment. Then they'll wish they'd given me a prize."

Wooden posts mark the ground where, in 1945, historian Roland Robbins discovered the remains of Thoreau's home. Nearby is a sign describing the cabin's appearance and its fate after Thoreau left Walden. The building was dismantled before 1850; its roof was put on a pigsty.

A glance around is usually enough for tourists, particularly those whose minds are on their vehicles. Most go no further than the cairn next to the sign. Beyond, the path narrows, and it is quieter; here is where one can hear the words of Thoreau.

We can hear him trying, perhaps, to drum up business for a vegetable-growing friend. "I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion," he says.

We can see him watching the leaves fall, or listening to dusk approach. "As the afternoons grow shorter, and the early evening drives us home to complete our chores," he writes, "we are reminded of the shortness of life, and become more pensive, at least in this twilight of the year."

We can imagine him thinking of time and twigs. "In Wildness is the preservation of the World," he writes, confident and concise. If he could transcend death and live today, he would write it again, in a still larger and bolder hand, on recycled paper. In Wildness (he would retain the capital) is the preservation of the World.

And in words is the preservation of Walden. Without Thoreau's legacy, the pond, which is more than a hundred feet deep in parts, would have docks, motorboats, and inflatables. Walden Woods would be a woods only in name; no benefits would be staged to save it from developers.

Words were written at Walden, and they consecrated it. To readers of Thoreau, the sound of these words will always be louder than that of cars on the nearby road or of picknickers crunching potato chips on the beach.

Walden is too remote for Harvard students without cars or maps to visit frequently. Those of us interested in wildness, the life transcendental, or the feeding habits of squirrels need go only when the weather is good or when we misplace our copy of Walden and want to be reminded of its deathless words. We need bring, at most, a pumpkin.

But in the meantime it is our task to do for our surroundings here in Cambridge what Thoreau did for his. We each need to create a Walden of our own; we need to fit words to places. We need to make clear our thoughts as we walk down JFK to the river, and articulate them to a friend or a journal page.

We need to play songs, over and over again, until we associate their lyrics with our rooms--the Ansel Adams poster above our dresser, the mess on our desk, the crooked light.

We need to find poems we have never read before and think of lines from them when we walk down Brattle Street, or get on the inbound T.

When you can visit a place and hear words--words you wrote about it, words you read when you were there--that place is a home, and sacred. When you hear words and feel as though you are in a certain place again, those words are exalted, and they form something like a prayer. Words can be summoned by Waldens, and Waldens can be summoned by words.

Our adventures are likely to be more subtle than Thoreau's, and less worthy of documentation and the general public's attention. No guidebook may ever point out the ledge of Widener where we sat, though it may figure prominently in tourists' slide shows. To us, though, it will be immortal.

"A man thinking or working is always alone, let him be where he will," Thoreau says. We don't have to live by ourselves or go to the woods to find Walden. It is here if we create it, and it will remain here. Whenever we return to it, we will be able to hear the echo of ourselves.