They’re filling in the West Side now. Every morning during the week, my wife and I awake to the cries of workmen high above our heads, putting the finishing touches on a glass tower that has already risen some 35 stories into the sky.

It is one of two towers that will face each other across Broadway, a matched pair of condominiums roughly twice the height of any other building for nearly a mile around. The one around the corner from us has already topped off, and when I look up it doesn’t seem quite real to me; more like an “artist’s rendition” of some absurdity from a children’s encyclopedia: How would the pyramids of the pharaohs look by comparison in the Manhattan of today? What would it look like if you plunged a gigantic, glass stiletto into a neighborhood of modest brick and stone apartment buildings?

It’s beyond me why dozens of individuals will pony up millions of dollars to stare out at the more-or-less mirror image of their own dismal glass box across Broadway, but then the real estate boom in this town long ago kicked off the last traces of rationality. Over the last few months, numerous businesses in low buildings along Amsterdam and Columbus Avenues have closed their doors, and the scuttlebutt is that these shops are to be demolished and replaced with more gargantuan high-rises. Three gracious old townhouses were razed just to make garage entrances for one of the new towers.

To help us make sense of the pace at which our neighborhood is being transformed, the local Bloomingdale Branch of the New York Public Library recently assembled an exhibit of maps, books and photographs illustrating other changes of the past 200 years. Bloomingdale (no relation to the store) was what much of the Upper West Side used to be called; a collection of farms and villages that persisted until the construction of the elevated railroad in the late 19th century. The library exhibit included pictures of this earlier seismic shift, including photos from the 1890’s of poor farm shanties and turned earth, residing cheek-by-jowl with five- and six-story apartment buildings. I had seen these photos and many others like them before, but I never cease to be amazed at how close we still are to that other, agricultural Manhattan that existed just over a century ago. (The mostly rusted fire escape on my own building bears a date of 1896, something that I don’t like to think about too much.)

The next photographs in the library exhibit, from the 1930’s, are still more astonishing. They show a landscape even more dense and thoroughly urbanized than it is today. The old farms are now completely buried, replaced by row upon row of tightly packed buildings and the elevated rail; all gray steel and stone. The elevated and all those buildings later vanished, too, as if they’d been made of air. The ground was cleared again to make way for “Manhattantown,” Robert Moses’s notorious 1950’s exercise in urban development on the blocks from Central Park West to Amsterdam, between 97th and 100th Streets. The project — later redubbed “Park West Village” — was widely condemned as a paragon of malfeasance and bad urban planning. Robert Caro, in his biography of Moses, “The Power Broker,” blames it for turning much of the Upper West Side into a slum overnight.

I don’t doubt Caro’s charges. “The Power Broker” is one of the best, most thoroughly researched urban histories ever written. It’s significant that his book’s subtitle is “Robert Moses and the Fall of New York.” Caro clearly believed that Moses’s arrogant, racist, car-crazy mutilation of the city really had killed it, that New York was down and it wasn’t coming back up.

Yet cities are remarkably resilient entities. It’s interesting how benign Park West Village and its surrounding public housing developments seem now — largely crime-free, filled in with trees and playgrounds, and full of families. Their buildings were constructed on a scale vastly more human than that of these glass excrescences that will overshadow us all.

Nor is my patch of the Upper West Side a slum, if it ever really was one. It certainly is different from when I first moved here, more than 25 years ago. Then you could still find Bowery-style bars along Broadway, where the floors were sprinkled with sawdust and serious drunks sat downing glasses of bad whiskey. The local bijou, the elegant Metro Theatre, was a porno house. A few blocks south, prostitutes worked the car trade from Jersey, even along expensive blocks between Broadway and West End Avenue. Later years brought new plagues — of break-ins and the crack epidemic, when we stepped outside every morning to find our stoops littered with tiny glass vials and burned-out match books.

I don’t miss those days, of course, but I will miss us. By that I mean so many of us who have lived and worked here all this time, and have strived to make it a better place. For years, my neighborhood has been preserved in a sort of no man’s land, a dividing line just beyond all sorts of furious gentrification. What developed was a remarkably diverse community — what New York is supposed to be, but so often is not. We are almost a joke about multiculturalism. My apartment building includes tenants whose antecedents are Sikh, Indian, Haitian, Ugandan, Puerto Rican, Dominican, Chinese, Ashkenazi, German, Irish and English. And nearly every possible definition of family is included: traditional, extended; gay parents with child; single mother with child; lovers; roommates; friends; and a single member of the transgendered community.

We may not all be best friends, but we manage to live together with remarkable harmony and good feeling. Many of my neighbors have indeed been here 20 years or more, and I have watched them slowly age as they have watched me, as we greet one another at the elevator or in the laundry room — a little paunchier, a little grayer and balder with every year, but still the same faces. I don’t like to think of us all gone, as surely and as suddenly as those seemingly imperishable buildings from the 1930’s.

Cities are all about loss, too. To remain resilient they must change, but the questions remain: What is any change for? And who will be left once it is done? Or are we to go on forever ploughing under and throwing up worse mistakes?

Maybe the great glass condominiums will outlast the handiwork of Cheops. But I take pleasure in spotting more humble survivors in my neighborhood: The church across the street that has been there for more than 150 years. The three-story, wooden building with a diner on the first floor, once a stagecoach stop on Bloomingdale Road. Surely something of us will live on, too. They can’t fill us all in, can they?