Frank Gunn, Associated Press Jane Jacobs is shown outside her home in 2000. She was an author and community activist whose classic "The Death and Life of Great American Cities" transformed ideas about urban planning. Click photo for larger image.

Jane Jacobs was a daughter of Pennsylvania, but her first and most influential book, about cities and the misguided attempts to plan them, made her a citizen of the world.

In her 1961 book, "The Death and Life of Great American Cities," Mrs. Jacobs was the first to challenge the federally funded highway and urban renewal projects and public housing policies that were devastating older neighborhoods in cities like New York and Pittsburgh.

The book, translated into Japanese and several European languages, was derided as the work of a novice by her critics, but she lived long enough to see it become a bible to later generations of architects and planners.

"It was the first really strong challenge to modernists' conceptions of urban renewal and rebuilding cities," Pittsburgh urban designer David Lewis said last night. "It reminded us that cities belong to people and the most successful streets are the streets that have the most people on them."

"A sacred text," architect Robert Stern called "Death and Life" in November 2000, moments before Mrs. Jacobs accepted the $25,000 Vincent Scully Prize at Washington, D.C.'s National Building Museum. It was a lifetime achievement award and a chance to say thank you to a woman who almost single-handedly changed the direction of American city planning.

With her son James nearby, Mrs. Jacobs died yesterday morning in her sleep in a Toronto hospital, just a few days shy of her 90th birthday. She had been in declining health and entered the hospital a few days ago.

The daughter of a doctor and a former school teacher, Jane Butzner was born in Scranton and moved to New York City in the 1930s, where she wrote for magazines and newspapers. During World War II, she worked in the Office of War Information, where she met architect Robert Jacobs, her future husband and mentor.

By the 1950s she was the mother of three children, a writer and editor at Architectural Forum and a neighborhood activist. In the early 1960s, she helped defeat powerful New York City parks commissioner Robert Moses' plan to run an expressway through Washington Square. Her observations of everyday life on Hudson Street in her Greenwich Village neighborhood were the basis of "Death and Life."

"Forty years ago, when most Americans held dense urbanism in considerable contempt, Jane Jacobs helped us see the city not as a terrible tyranny but as a great liberation, the ultimate freedom," Mr. Stern said at the awards ceremony in 2000. "She did this with a book, which burst on the scene with a force quite unlike that of any previous book" -- a book "so cogent and so sensible that real people could actually participate in an intelligent discussion of architecture and urbanism."

Mrs. Jacobs was against interstate highways plowing through city neighborhoods and against the generic, homogenous suburbs they fed. She was for organic growth and economic and cultural diversity; short, walkable blocks with attractive sidewalks; apartments above stores; and buildings oriented to the street. She favored all that protected the "social capital" of the city, the human relationships that make the city hum.

"She saw that a whole structure of professional thought and practice relating to the city was indeed destructive of the city," said Dr. Scully, Yale professor emeritus, at the presentation of his namesake award. "She perceived and convinced a vast public that something which everyone believed was right was in fact utterly wrong."

In a 2001 survey conducted by Columbia University, Mrs. Jacobs surfaced as the writer/theorist who most influenced the thinking of the nation's architectural writers and critics.

Because of their opposition to the Vietnam War and a desire not to see their two teenage sons drafted to fight in it, Jane and Robert Jacobs moved their family to Toronto in 1968; Mrs. Jacobs became a Canadian citizen in 1974.