From the time she was a young girl, Jane Jacobs' curious mind made her a keen observer of everything around her. When she grew up, she moved to New York City, a place full of new wonders for her to explore. It was there she realized that, just like in nature, a city is an ecosystem. "It is made of different parts -- sidewalks, parks, stores, neighborhoods, City Hall . . . and people, of course. When they all work together, the city is healthy."...