American-Canadian writer on cities, economies, and community life; the most consequential 20th-century critic of the modernist planning consensus and one of the most original political economists of her time — and all of this as someone who never finished college, held no academic appointment, and worked outside the credentialed professions whose received wisdom she spent her career dismantling.
The Death and Life of Great American Cities (1961) is her central book. It was written against the reigning orthodoxy of postwar American urban planning — the slum-clearance, towers-in-the-park, freeway-through-the-neighborhood consensus associated in New York with Robert Moses and in the profession generally with Le Corbusier's functionalist vision — and against its demonstrated effects on the neighborhoods it cleared. Jacobs's counter-argument was grounded in close, patient, street-level observation of what actually made city neighborhoods safe, sociable, and economically vital: mixed uses (not residential-only zoning), short blocks (not superblocks), a density of buildings of varied age (not wholesale redevelopment), and a sufficient concentration of people (not depopulation through "decongestion"). The famous opening chapter on "the uses of sidewalks" reframed the sidewalk as the organ of urban safety — "eyes on the street," the incidental, continuous surveillance of ordinary life — rather than as leftover space between buildings. The book effectively ended the authority of orthodox urban-renewal planning and set the terms for everything American cities have tried to do since.
She went on to argue, in The Economy of Cities (1969) and Cities and the Wealth of Nations (1984), that cities and not nations are the actual units of economic life — that economic development happens through the import-replacement dynamics of working cities, and that national economic theory miscalibrates what it is looking at. Systems of Survival (1992) distinguished two incompatible moral syndromes — the commercial (honesty, initiative, competition, voluntary agreement) and the guardian (loyalty, hierarchy, tradition, use of force) — and traced the corruption that follows when either tries to operate by the other's rules. Jacobs moved to Toronto in 1968 in part to keep her sons out of the Vietnam draft; she spent the second half of her life there, fighting similar planning battles against the Spadina Expressway and eventually becoming one of the most widely cited Canadian public intellectuals.