If you live or work in a successful American city, Jane Jacobs’s influence is pervasive, though you may not recognize it. It’s there in the new “mixed-use” development, with its sleek condos and boutique commerce and proximity to schools, and there, too, in the bustling neighborhood, rescued from the wrecking ball a few decades back, where old apartments now sell for millions. And it’s there in the way we view cities—not as fated to entropic collapse but as potentially vital, surging with economic and cultural creativity and renewing themselves ceaselessly.

Lacking official academic credentials, Jacobs, who died at 89 in 2006, used her formidable intelligence, eye for telling detail, and lifelong distrust of authorities to educate herself about how urban areas prosper. She authored several important books, mostly about cities, including the 1961 classic, The Death and Life of Great American Cities, which transformed urban planning forever. Along with her writing came a side career as a community activist. Most famously, she went to war against New York’s powerful master planner Robert Moses and won, saving her beloved Greenwich Village from “urban renewal” and lower Manhattan from destruction by expressway. Given Jacobs’s prominence, it’s surprising that no full biography had appeared before Robert Kanigel’s Eyes on the Street arrived in late 2016, marking the centenary of its subject’s birth. It’s unlikely to be matched in comprehensiveness any time soon. A one-time Guggenheim fellow and author of The Man Who Knew Infinity (1991), a biography of mathematician Srinivasa Ramanujan recently made into a film, Kanigel also writes with admirable clarity.

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Jane Butzner was born into a middle-class family in then-prosperous Scranton, Pennsylvania. Her father, John “Decker” Butzner, was a doctor; her mother, Bessie, had trained as a nurse. Evidence of Jacobs’s intellect appeared early. As a kid, she carried on imaginary conversations with Thomas Jefferson—he “always wanted to get into abstractions,” she would say—and the more down-to-earth Benjamin Franklin. She also read everything she could get her hands on and wrote poems, publishing one in American Girl in 1927. But she was a disorderly student, constantly scrapping with teachers. In fourth or fifth grade, for example, her teacher pronounced that wearing boots would hurt one’s eyesight. “Silly,” thought Jane, and her ever-rational father agreed. She began to stomp around school in rubber boots, taunting her teacher: “See my eyes? Look at ’em—they’re just fine.” School mostly bored her.

Jane Butzner’s path to becoming Jane Jacobs, urban visionary, was winding. She enrolled in Scranton’s Powell School of Business in 1933, where she learned to take dictation and type, and developed other practical skills that would come in handy in Depression-era America. She subsequently took an unpaid position at a Scranton newspaper, covering weddings and local politics and writing reviews. Then she spent time with her Aunt Martha, a Christian missionary, in Higgins, North Carolina, a backwater where basic know-how had eroded and people were so poor, she later wrote, “that the snapping of a pitchfork or the rusting of a plow posed a serious financial crisis.” Each of these experiences proved formative. Business classes grounded her; newspaper work taught her how to report and meet deadlines; and living in Higgins planted a question in her mind: how could the town’s condition have gotten so dire?

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In mid-November 1934, at the Depression’s nadir, Jane moved to New York City. She wanted to be a writer but initially took on a series of low-paying clerical jobs, living with her older sister Betty in Brooklyn. Jane began exploring the city, taking the subway to random stops, getting out, marveling at New York’s worlds-within-worlds. One such stop, Christopher Street in Greenwich Village, particularly charmed her, and she and Betty soon moved to the bohemian neighborhood. Over the next 33 years, Jane had three homes in New York City, all in the Village.

Jacobs’s big break as a writer came in the pages of Vogue, which ran her over-the-transom profile of New York’s fur district in late 1935. They paid her $40—three times what a week of typing brought in—and asked for more. She enrolled in Columbia University’s continuing education program, taking classes in economic geography, geology, zoology, and constitutional law, and “loving every minute of it,” Kanigel writes. Reading deeply for the law course, she compiled a selection of ideas considered but rejected during the Constitutional Convention, proposed it as a book to Columbia University Press, and got it published as Constitutional Chaff (1941)—a remarkable achievement for a young woman just out of high school.

When war arrived, ending the Depression in the fever of military production, the U.S. Office of War Information hired Jacobs to promote the Allied cause. She excelled, winning big assignments and a supervisory role. She also got married. Bob Jacobs was an architect, employed at the time at a military aircraft complex in Long Island. It would be a life match, based on a profound friendship.

After the war, Jacobs went to work for Architectural Forum. Bob patiently showed her how to read blueprints, and she wrote up a storm on shopping malls, hospital design, and other assigned topics, adding to her idiosyncratic store of knowledge. Meantime, the themes of Death and Life germinated. A crucial moment occurred in 1955, when Jacobs traveled to Philadelphia to cover the city’s heralded urban renewal under planning commissioner Edmund Bacon. He first showed Jacobs a black neighborhood, set to be bulldozed; this was his bad “before.” It was dirty and run down, Jacobs noticed—but teeming with people. Then Bacon showed her his “after”: a fine new housing project, rising up majestically over what was once a similarly beaten-down street. The neighborhood was much cleaner—but lifeless. All Jacobs could see was one little boy, glumly kicking a tire. “Where are the people?” she asked.

Jacobs discovered something similar in East Harlem, New York. East Harlem’s vast Franklin Houses provided 1,200 public-housing apartments, but the project’s construction had pushed out some 200 small shops and community organizations, from grocers to political clubs—the lifeblood of an impoverished but functioning tenement neighborhood—leaving a social void.

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Jacobs grew dubious about the age’s consensus on cities. The planners and their establishment allies were “seized with dreams of order,” she believed, their guru the modernist Swiss-French architect Le Corbusier, celebrant of the “Radiant City” of tomorrow, where people lived in gleaming towers, surrounded by green parkways, all the disorder of the old, messy city scrubbed away. No more chaos on city streets, in Le Corbusier’s geometric ideal: living would be done in one place, shopping in another, and manufacturing in yet another. But was this still a city, Jacobs wondered? Funded by a Rockefeller Foundation research grant and an advance from famed editor Jason Epstein, Jacobs took leave from Architectural Forum to turn what she had seen, and what she now believed, into a book.

Writing took longer than expected, but when it finally appeared, The Death and Life of Great American Cities was an event. “Under the seeming disorder of the old city, wherever the old city is working successfully,” the book announced, “is a marvelous order for maintaining the safety of the streets and the freedom of the city.” It was not the dead regime imposed by top-down planners but a “complex order,” built up from the countless arrangements of civil society. What made it possible, Jacobs argued, was an “exuberant diversity,” resting on four conditions. First, the modernists got things exactly wrong in slicing up city life into functional components; a vital neighborhood should meet multiple needs, offering places to live, socialize, work, play, and learn. A jumble of primary uses put people on the sidewalks at all hours, which meant “eyes on the street,” watching for potential threats to the community. Short blocks, a second condition, encouraged variety in walking paths, unanticipated encounters, and opportunities for businesses to find new clients. Long blocks, by contrast—especially the “super-blocks” favored by city planners for public housing or other large-scale urban projects—brought only stagnation. And old buildings shouldn’t always get ripped down, Jacobs contended. Often with low rents, they could be repurposed as inexpensive incubators of new uses and ideas. Finally, density wasn’t bad, as the planners claimed, but an urban advantage. “In cities, liveliness and variety attract more liveliness; deadness and monotony repel life,” observed Jacobs in one of Death and Life’s numerous striking formulations.

Epstein praised The Death and Life of Great American Cities as “the most exciting book on city planning that I have ever read—and one of the most exciting books on any subject I have ever seen.” Major magazines lined up to run excerpts and reviews. Not every notice was favorable. Urbanist Lewis Mumford, writing in the New Yorker, blasted “Mother Jacobs,” as he sneeringly called her, for “faulty data, inadequate evidence, and startling miscomprehensions of views contrary to hers.” But he took 8,000 words to go after the book, underscoring its importance.

Though Jacobs emphasized that there was “no direct, simple relationship between good housing and good behavior,” Death and Life at times gave the impression that urban design determined community vitality. Maybe some neighborhoods thrived because of the kind of people who lived there, not the length of blocks or mixture of uses. And Jacobs wrongly downplayed the role of policing in neighborhood security. Eyes on the street weren’t sufficient to keep American cities safe during the 1970s, ’80s, and into the ’90s, when crime rates exploded; it took major shifts in police methods and deployment to restore order. Her hostility to suburbs as life-sapping was also overstated. Still, Jacobs won the main argument. Among city planners and urban architects these days, everyone is a Jacobean, or claims to be.

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Even as she was becoming an intellectual celebrity, Jacobs found herself drawn into community activism. She had a talent for it, says Kanigel, though defeating Moses and his plans to ram highway traffic through whole swaths of Manhattan required different skills “than blue-penciling a recalcitrant paragraph.” Jacobs “the scrappy street fighter” had to make deals, issue public statements, write letters, sit through boring public meetings, and appeal to, or threaten, friends and enemies alike. She detested Moses, whom she claimed “did more harm to New York City than any other hundred men you can imagine put together” And he hated her. When Death and Life’s publisher, Random House, sent a copy to Moses, he fired back: “I am returning the book you sent me. Aside from the fact that it is intemperate and inaccurate, it is also libelous…. Sell this junk to someone else.” Kanigel gives relatively short shrift to the struggle between Jacobs and Moses, perhaps because other books, such as Roberta Brandes Gratz’s The Battle for Gotham: New York in the Shadow of Robert Moses and Jane Jacobs (2010), have covered it in detail. He is right to observe, however, that Jacobs’s hard-fought victories marked the beginning of Moses’s downfall.

In the summer of 1968, the Jacobses, vocal opponents of the Vietnam War and worried that their two sons would be drafted, left their beloved Village and moved to Toronto. Bob landed a job with a Canadian architectural firm, and Jane was soon clashing with local planners over yet another proposed expressway, joining forces with media theorist Marshall McLuhan and other activists to quash the plan. Jacobs eventually became as much a Torontonian as she had been a New Yorker, selling jam at the neighborhood fair and sitting on her front porch watching kids on the sidewalk, practicing the virtues of civil society.

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The Economy of Cities came out about a year after the Toronto move, and, in a quieter way, would become as influential as The Death and Life of Great American Cities. Its central contention was that cities ignited economic growth—but only when they generated new forms of work. Consider Los Angeles. The city hemorrhaged more than 200,000 jobs in shipbuilding and aircraft manufacturing in World War II’s immediate aftermath, yet generated an increase in overall employment over the same period. What occurred, Jacobs explains, was a remarkable burst of innovation, as small firms started making products previously imported into the city and began exporting them—sliding doors, hospital equipment, tools, and much else. Fueling this creative explosion was an adaptive process through which one kind of work was extended into new kinds—the way New York dressmaker Ida Rosenthal invented an early brassiere to perfect the fit of her garments. Dressmaking was “old work,” wrote Jacobs; brassieres were “new work.” When cities stop innovating and adapting, economic stagnation is inevitable—witness Detroit and its car-dominated economy, already in decline when The Economy of Cities hit bookshelves.

Jacobs was not a number cruncher, and was an autodidact, but The Economy of Cities and its sequel, Cities and the Wealth of Nations (1984), which applied its theories to the global economy, gained a significant following among academic economists. Chief among them was the University of Chicago’s Robert Lucas, whose human capital writings won him a Nobel Prize in 1995. He found exciting Jacobs’s emphasis on ideas as drivers of growth—and her recognition that cities were good for ideas because they brought so many bright people together. “Ideas get put into use, they arise from different cultures and bodies of knowledge meeting each other,” Lucas noted. Harvard economist Edward Glaeser, acknowledging Jacobs’s influence, has made the entrepreneurial might of urban “agglomerations” central to his research, popularized in his brilliant 2011 book, Triumph of the City.

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Nothing that Jacobs would go on to write would match the remarkable influence of Death and Life and The Economy of Cities. Systems of Survival (1992), written as a fictionalized symposium, examines the “web of trust” among strangers that sustains social and economic life, seeing it as built on two distinct, and necessary, moralities: that of “Guardians,” who use force and guile to protect society, and that of market actors, who practice the soft virtues of commerce. The Nature of Economies (2000), another symposium, interprets economic life as akin to nature in that both involve “differentiation emerging from generality”—basic things developing into more complex things. In her final book, Dark Age Ahead (2004), Jacobs warned about five pillars of civilization that were “dangerously close to the brink of lost memory and cultural uselessness”: family and community, higher education, science and technology, government, and learned societies. All these books, Kanigel points out, feature striking observations and insights, even if they’re less successful than Jacobs’s early masterworks.

Few thinkers can claim to have had a significant influence on one area of life. Jane Jacobs could justly claim she had it on three: the way we think about neighborhoods and urban vitality; the way we think about economics and human capital; and the actual fates of New York and Toronto, two cities that would look much different if the planners had had their way. In Robert Kanigel’s Eyes on the Street, she now has a biography worthy of her extraordinary achievements.