It was late Tuesday night when I heard that Jane Jacobs died. But I was in the middle of editing my documentary, too zoned out from lack of sleep and stress to pause, or process.

Jane Jacobs, I had always told anyone who didn’t know of her, was the woman who saved New York. And, by extension, all American cities.

In the 1950s she was living with her architect husband on Hudson Street in Greenwich Village. On a tip from her spouse, she got a secretarial job at a magazine, Architectural Forum. “By the way,” they said, “you’re also our hospitals and schools editor.”

Thus began, quite by accident, her writing career and her introduction to modern “Urban Renewal.” Unencumbered by training or indoctrination or loyalty, Jacobs quickly discerned that the explosion of urban building — expressways, housing projects, civic centers, and other well-intentioned public works — were instead destroying cities, annihilating the elegant balance of elements that actually made cities work.

This insight got full expression in her 1961 book, “The Death and Life of Great American Cities,” which, from out of nowhere (and from a nobody), completely rocked the urban planning establishment. In simple and sometimes sarcastic language, she simply destroyed the prevailing myths and principles that most people took for granted simply because those theories came from “experts.”

Jacobs derided the lofty Corbusian vision of “towers in a park” that became the blueprint for the superblock housing project. Why, she asked, do these theorists think that “grass, grass, grass” is the answer for urban problems? These projects, which looked so impressive on paper, inevitably became places of worse anomie and crime, with those grassy areas deserted, with grand “promenades that went from nowhere to no place and had no promenaders.”

What did Jacobs celebrate? The block. The corner. The mess of cities. The mix of old and new buildings that kept incomes and ethnicities varied. The mix of uses that always kept “eyes on the street,” making it safer everyone, especially children. She even acknowledged the need for great public works and industry uses that didn’t necessarily lend themselves to street life.

It’s this point that gets ignored by a lot of writers and theorists who have turned on Jacobs, like Nicholai Ouroussoff in the New York Times, unfairly making her name synonymous with the contemporary fetishing of the “neighborhood”: the quaint, antiseptic Gap and Gymboree gentrification that stifles the lifeblood of cities in different ways.

But unlike most armchair experts, Jacobs walked her talk. She was active in protesting the demolition of New York’s Pennsylvania Station — which led to the forming of the city’s first landmarks preservation process. Most famously, she foiled New York’s master builder Robert Moses in his plan to eviscerate of Washington Square Park, and to drive the Lower Manhattan Expressway through Soho and Chinatown, which would have destroyed the Cast Iron District. It did not, because of her.

I thought of Jane Jacobs a lot in the years leading up to my eventual return to New York, for it was she who articulated best the reasons why I could no longer stand to be in a place like Los Angeles. She became, in a sense, an unseen but powerful mentor for me.

Luckily, I had a chance to meet my mentor before she passed, when she gave a talk in San Francisco in May of 2004. At 87, she was on a book tour, believe it or not, for her last tome, “Dark Time Ahead.” She was this frail, hunched-over remnant of a woman, but when she spoke, her voice shook the room. “Anecdotal evidence,” she said, “is really underrated,” defending human reason against the tyranny of research and analysis. When she padded onto the stage in a walker, she got a standing ovation. And when she held an insanely huge megaphone to her ear so she could hear questions from the audience, she got a huge laugh. Afterward, when I got her to sign my copy of “Death and Life,” I told her that I had recently moved back to New York. “Good for you,” she shouted.

That autographed book now sits on the shelf in my apartment as I go about my busy New York life,. A life too busy, I thought, to mourn or reflect on her passing, or even write of it in a blog with a title inspired by her. How ironic.

Until I remembered that I now worked on Hudson Street.

It hadn’t even occurred to me. So yesterday, on a lunch break that I don’t usually take, I stepped into the sunshine and walked from 304 Hudson, past new office buildings and old factories repurposed into gyms and storage warehouses, and into the Village, watching the buildings become smaller, older. Watching children suddenly appear. Shopkeepers sweeping the sidewalk. Bustling cafes with lunchtime traffic.

I walked north until I came to 555 Hudson Street. It was from this building that Jane Jacobs watched her block and, in so doing, discovered how cities work.

I bought some flowers and left them with a small group of offerings that others had left in the wooden doorway, one of which read: “Jane Jacobs, 1916-2006. From this house, a housewife changed the world.” I left my own words, scrawled on a business card bearing my first New York address in 15 years:

“Jane—Thanks for bringing me home.”

After that, it was easier to fight my primal urge to rush back to work. So I stopped at the White Horse Tavern at the end of the block, had a burger and a beer to salute old Mrs. Jacobs, and watched life walk by.