IN 1951, THE LITERARY CRITIC Alfred Kazin prematurely published an autobiography. It is mostly an account of his growing up in certain Brooklyn neighborhoods, Brownsville in particular. The main character, of course, is Kazin, who is now what is called a New York intellectual. Another character, though, is the Brooklyn neighborhood of his youth. Kazin called his book A Walker in the City. It's a pathetically nostalgic title. Now such a walker would be mugged.

Do I exaggerate? Honestly, I do not know. The last time I was in Kazin's old neighborhood, I was saddened. Many of the buildings had been torched and then boarded up. Places of worship had been converted as the neighborhood changed, and then they too had been abandoned. The place looked menacing, dangerous. I accepted it at face value. I would not walk there.

I have no nostalgia for Brownsville (and neither, as far as I could tell, did my grandmother who lived there), but I do have nostalgia for the American city -- the city of old, the safe city. I am talking now of many cities, not just New York. I am talking about Chicago and Philadelphia, Cleveland and Detroit. I am talking too of Washington, which is my city and which, like all the others, has lost population not just because the houses are bigger in the suburbs but because this place, this city, this capital of the United States, is not safe anymore.

Detroit has set some sort of record. It's the first American city to have had more than 1 million people and to then fall below the mark. That city is sinking like a ship, people climbing over the rail to get off. Cleveland is not much better off, and Chicago isn't what it used to be either. You name an American city -- a true city, not some Sunbelt collection of housing tracts -- and the story's the same: People are either fleeing or have fled. Philadelphia has lost 500,000 people since 1950. Philadelphia is a great city. This is a tragedy.

Why? Because cities are incubators and repositories of culture. Kazin wrote about Brownsville and Brooklyn and New York. Who ever wrote about McLean or Arlington -- or any suburb, for that matter? Saul Bellow and Carl Sandburg not only wrote in Chicago but about Chicago. I'm not saying that culture exists only in cities or that no one ever wrote a good book about the suburbs. I'm just saying what's obvious: The city is to culture what the desert is to sand. There's some of the stuff elsewhere, but it doesn't amount to much.

In fact, it's almost impossible to think of art without thinking of cities, whether that art is theater or painting or dance. This is not to say that, say, painters cannot paint elsewhere -- they do and they have -- but they come together, they exhibit and, in their early and formative years, they learn in cities. Think of Paris. Think of Picasso and Braque -- not just that they painted in Paris, that they exhibited there, but that these two artists exchanged innovations there. You cannot produce cubism on the phone.

The city . . . the city is where I always wanted to live. The city is a place of nearly sexual excitement to me. I could see the skyline of the city from the New York suburb where I was raised. On a clear day, I felt I could reach out and touch it. The moment I could, at 18, I left home for the city. I did things that are now not possible, not safe anyway. I walked any street I wanted any time I wanted. On hot nights, I camped in Central Park. I rode the subways at 3 in the morning. I was what is no longer possible: a walker in the city.

My friend asks, "Can you imagine the Brits letting London go to the dogs?" No, I say, nor the French Paris. But if you make one city out of Washington and New York -- if you combine the political capital with the cultural and financial capital -- then you have a single city with the highest robbery (New York) and murder (Washington) rates in the country. You have a single city that much of the country rightly considers dangerous, that is losing population, a horrible place where children are killed by stray bullets.

Consider my car. It's as much a response to crime as the Batmobile. Both are equipped to cruise the contemporary American city. Mine has an alarm system, automatic locks and a valet key so that even the parking lot attendant can't get into my trunk. My car is like a city dweller's house or apartment. This is no way to live.

Who is to blame for this state of affairs? It's the wrong question, totally nonproductive, but I'll answer it anyway. Liberals are to blame for some of our silly notions and conservatives for being stingy and not caring. We are all to blame for what we have done and what we continue to do. Americans treat their cities the way they would not treat some endangered owl. "SAVE THE CITIES" bumper stickers are never seen, and, if they were, most of the country would laugh. Save the cities? Hah. Those people!

Yes, those people. For they are mostly good people, and, better than that, they are city people. They do not just passively accept the American culture, the way suburbanites do, but confront it, enrich it and, in this way, change it. They live in a place, the city, where culture is manufactured. But some of them are leaving that behind, some fleeing. They go because traffic doesn't move and the streets are dirty and the schools don't work. They go for a lot of reasons, including a yen for a lawn. But more and more they leave because they are afraid. Not since Rome was sacked has anything like this happened. Not for nothing was the period after that called the Dark Ages.