Answer by taking a quote from the following article:

Jane Jacobs  (born Jane Butzner; May 4, 1916 - April 25, 2006) was an American-Canadian journalist, author, and activist who influenced urban studies, sociology, and economics. Her book The Death and Life of Great American Cities (1961) argued that urban renewal did not respect the needs of city-dwellers. It also introduced the sociological concepts "eyes on the street" and "social capital". Jacobs organized grassroots efforts to protect neighborhoods from "slum clearance", in particular Robert Moses' plans to overhaul her own Greenwich Village neighborhood.

She became a feature writer for the Office of War Information, and then a reporter for Amerika, a publication of the U.S. State Department. While working there she met Robert Hyde Jacobs Jr., a Columbia-educated architect who was designing warplanes for Grumman. They married in 1944. Together they had a daughter, Burgin, and two sons, James and Ned. They bought a three-story building at 555 Hudson St. Jane continued to write for Amerika after the war, while Robert left Grumman and resumed work as an architect.  The Jacobses rejected the rapidly growing suburbs as "parasitic", choosing to remain in Greenwich Village. They renovated their house, in the middle of a mixed residential and commercial area, and created a garden in the backyard.  Working for the State Department during the McCarthy era, Jacobs received a questionnaire about her political beliefs and loyalties. Jacobs was anti-communist, and had left the Federal Workers Union because of its apparent communist sympathies. Nevertheless, she was pro-union and purportedly appreciated the writing of Saul Alinsky; therefore she was under suspicion. On March 25, 1952, Jacobs delivered a now-famous response to Conrad E. Snow, chairman of the Loyalty Security Board at the United States Department of State. In her foreword to her answer, she said:  The other threat to the security of our tradition, I believe, lies at home. It is the current fear of radical ideas and of people who propound them. I do not agree with the extremists of either the left or the right, but I think they should be allowed to speak and to publish, both because they themselves have, and ought to have, rights, and once their rights are gone, the rights of the rest of us are hardly safe ...

What is the relevance of Amerika to Jane Jacobs?
reporter for Amerika, a publication of the U.S. State Department.