"What a dear, sweet grandmother she isn't," a critic once said of Jane Jacobs, conjuring the combative urban visionary as we remember her: owlish glasses and bobbed hair, dueling with Robert Moses and Ivy League-educated city planners, marching against the Vietnam War, a rebel with many causes. In his sparkling new biography of Jacobs, Robert Kanigel brings to life the woman behind the legend. "Eyes on the Street" is a nuanced, intimate portrait of this influential if arrogant figure whose theories transformed the ways we view our cities.

Born in Scranton, Penn., in 1916 to a forward-thinking physician and his volatile wife, Jane Butzner grew up surrounded by spirited debate. She was always encouraged to express her opinions openly and to question conventional wisdom. She was a mediocre student at best; her formal education essentially ended after she graduated from high school. At 19 she moved to Depression-era New York City, where she sponged up stray bits on topics from geology to embryology to metallurgy, and even compiled a quirky book, "Constitutional Chaff: Rejected Suggestions of the Constitutional Convention of 1787."

Eventually she began to write for pay, Vogue articles morphing into a regular gig at Architectural Forum. Along the way she married an architect and started a family, championing her beloved West Village and building a fan base with her fresh observations and caustic wit.

Her big break came when she gave a galvanizing 10-minute lecture at Harvard on the thorny questions of urban renewal. Overnight this autodidact became a celebrity, an authority on city planning, sought after by leading academics and pundits, which culminated in her 1961 masterpiece, "The Death and Life of Great American Cities."

New York was always her compass. "Dark or bright, gritty or grand, the Manhattan skyline inimitable, the poorer quarters seen with affection, horror, or shame. … And now Jane's own strong feelings for the city, long sublimated in her magazine articles, or surfacing only in table talks with friends, were to join the great conversation."

Kanigel is superb at fleshing out Jacobs the woman; he's less adept at showing how her ideas evolved and were embraced across the world. "Eyes on the Street" is a personal story, not an intellectual history. The last third of the book is the weakest. With her two college-age sons ripe for the Vietnam draft, Jacobs and her family literally sneaked away one morning to Toronto, where she lived out her remaining decades, writing increasingly abstract tomes about economics and luxuriating in her fame.

Partly this is Jacobs' fault — her Canada years were far less relevant than her creative apotheosis in New York — but Kanigel gets swept up into the myth, his tone effusive, his storytelling pared down to bare bones.

But these are minor quibbles when compared with the dazzling merits of "Eyes on the Street." It's an exhaustively researched, beautifully rendered tale, revealing the human contours of a vigorous, original mind.

Hamilton Cain is the author of "This Boy's Faith: Notes From a Southern Baptist Upbringing." He lives in Brooklyn, N.Y.

Eyes on the Street
By: Robert Kanigel.
Publisher: Alfred A. Knopf, 482 pages, $35.