Aldo Leopold (1887-1948) is often described as the father of environmental ethics. His seminal book, “A Sand County Almanac,” was first published 75 years ago and remains a foundational text in nature writing. Still in print, it’s a classic in the classroom and, as Barbara Kingsolver has written, “the manifesto of a movement.” It is full of memorable, finely observed writing and is a landmark in American philosophical thought.

Among his many followers, Leopold is a legend. Awards, educational foundations, a research institute and even a section of wilderness in a national forest bear his name. His former home is listed in the National Register of Historic Places. In an introduction to Oxford University Press’s 70th-anniversary edition of “Almanac,” Kingsolver noted that it is one of the very few books she reads at least once a decade. One of Leopold’s biographers, Curt Meine, told me that “for many readers, it is revolutionary, life changing.”

But I confess that, while I marveled at Leopold’s prose — so vividly descriptive, insightful and witty — as a city girl far removed from wilderness, who never felled an oak tree or shot a wolf or shot really anything, I struggled to genuinely comprehend his more challenging philosophical arguments. Until I saw the cranes.

As the air quickly cooled and the sun gradually sank below the horizon, turning the sky from blue to pink to gold to a fiery orange, the pageantry began. Tens of thousands of long-necked, graceful sandhill cranes emerged above the Nebraska prairie, crisscrossing the open space as if they were weaving a tapestry across the heavens. Their distinctive call announced their entrance; it was not melodious like that of many birds, but piercingly loud and cacophonous, with a vibrating rattle – a primordial cry that long precedes our time on Earth.

Every spring for millions of years, these cranes have swooped down to the meandering streams and shallow banks of the Platte River to rest and nourish themselves on their long, arduous trip up north. It is now the largest migratory gathering in North America, one of the last great migrations left on the planet.

Witnessing this astonishing sight at sunset as the cranes settled in for the night, and as they awakened before dawn the next morning, gave me a glimpse into Aldo Leopold’s world.

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“A Sand County Almanac” was born in a dark time and under tragic circumstances. Written in the aftermath of World War II, when ferocious new technologies were unleashed and open space was gobbled up by automation, the book is a collection of short essays mostly written later in Leopold’s life, after a career spent teaching, researching and advocating for wildlife conservation.

Stylistically, its lyrical observations woven with a groundbreaking philosophy had few antecedents. Perhaps that is why the manuscript was rejected four times by other publishers before Oxford agreed to publish it. That was in mid-April 1948. A week later, while battling a wildfire on a neighbor’s property near his family’s shack in the sand country of central Wisconsin, Leopold suffered a heart attack and died. He was 61.

“Almanac” was published the following year. Leopold never knew of its success and its status as a conservation classic, with more than 2 million copies sold worldwide, translated into 15 languages.

The book is divided into three parts, the first of which is the true almanac, written from his Wisconsin shack, one essay for each month of an annual cycle. It is earthy, detailed writing — the beginning of the year is marked by tracing skunk tracks across the fresh snow.

One of my favorite passages comes in February, when Leopold and helpers sawed through a massive branch from an oak tree that had been struck by lightning the prior summer. The arduous task became a poetic history lesson, each ring of the oak representing another moment in time as they bisected the wood, through the 20th century into the 19th, reversing nature and human development to arrive at the core.

“Our saw now cuts to the 1860s, when thousands died to settle the question: Is the man-man community likely to be dismembered?” he writes. “They settled it, but they did not see, nor do we yet see, that the same question applies to the man-land community.”

Appreciating Leopold’s ability to see “the theatre of evolution” in nature is the first step toward understanding the more complex philosophy he outlines in the book’s third section. In it he argues that the ethical behavior we strive for among individuals, and between individuals and society, must be extended to the individual’s relation to the land and the animals and plants that grow upon it.

This land ethic, he writes, “enlarges the boundaries of the community to include soils, waters, plants, and animals, or collectively: the land. … [This ethic] changes the role of Homo sapiens from conquerors of the land-community to plain member and citizen of it.”

He decried the dominant role of economic self-interest in conservation and the tendency to relegate to government the necessary jobs that private landowners fail to perform. Instead, he encouraged development of an “ecological conscience” and a “conviction of individual responsibility for the health of the land.”

As Susan Flader, another Leopold biographer, told me, this was “a pioneering thought” meant to raise awareness of the land not for exploitation, dominance or even recreation, but as an essential element in an integrated worldview.

But how is this accomplished? This is where I struggle. Leopold doesn’t promote specific policies but rather a dramatic shift in values that can be difficult to imagine for those of us removed from routine interactions with nature. This struck me especially as I read the second section of the book, a series of essays recounting episodes in his life that he found illuminating and that I often found challenging.

He laments the decline of the passenger pigeon, the fleeting chance to canoe down a wild river, the loss of wilderness itself. He recounts the chilling realization that shooting a wolf — and watching “a fierce green fire dying in her eyes” — may eliminate a predator but, repeated again and again, leads to the decimation of the ecosystem necessary for mountains, plants and other animals to flourish. The evocative writing is persuasive, but can I fully mourn the loss of something that I never experienced myself?

Then I saw the cranes, and I understood.

In one of his most famous essays, “Marshland Elegy,” Leopold described the crane migration that he witnessed each year from his Wisconsin farm, where many of the sandhills stop to spend the summer or pass through on their way north. As the marshland withered under new roads and development, the ancient migratory pattern was disrupted by what Leopold derisively called “the high priests of progress.”

He concluded with a heartbreaking premonition. Someday, he wrote, “the last crane will trumpet his farewell and spiral skyward from the great marsh. High out of the clouds will fall the sound of hunting horns, the baying of the phantom pack, the tinkle of little bells, and then a silence never to be broken, unless perchance in some far pasture of the Milky Way.”

Leopold’s vision, usually beautifully rendered and optimistic, here is laced with doom. And writing in the 1940s, watching the beloved marshland quickly disappear, he clearly believed that he was offering a eulogy.

But on a frigid morning before dawn last March, I quietly took my place with a small group in blinds lined with windows on the prairie adjacent to the Platte River. No loud voices, no camera flashes, nothing to disturb the cranes in their habitat.

As a thin orange ribbon sliced through the dark sky in the east, thousands of cranes that had spent the night clustered in shallow waters, protected from predators, stirred, then squawked, then began gradually to take flight. They are canny birds that are never alone – they mate in pairs for life, move together in family-like flocks, and soar with astonishing strength and grace.

I was captivated by this dramatic yet meditative scene, and grateful. When Leopold wrote “Marshland Elegy,” the sandhill crane population was at historic lows, and their gorgeous cousin, the whooping crane, was nearly extinct. Now, thanks to prodigious conservation efforts, hundreds of thousands of sandhills migrate across America every year, and whooping cranes are being replenished; we saw a pair roosting on the riverbank.

To appreciate Leopold’s legacy, do we have to witness wilderness ourselves? Perhaps. But I hope that his slender “Almanac,” prescient and still relevant, would help transport even a city girl to the metaphorical wilderness to grapple with its demanding message. “We abuse land because we regard it as a commodity belonging to us,” Leopold wrote. “When we see land as a community to which we belong, we may begin to use it with love and respect.”

Jane Eisner is the former director of academic affairs at the Columbia School of Journalism. Her book about Carole King will be published next year by Yale University Press.