What impact did the book "The Shame Of Cities" have on America?I don't have a clear understanding of the content.

I would say that one of the largest impacts of the book was to bring attention to the idea that business growth cannot be divorced from social responsibility.  Cities had become an industrial center at the outset of the 20th century and with such a role came some defining elements.  Urbanization had led to crowded and cramped conditions, filled with individuals who had become cogs in the machinery of economic progress.  These centers of urban population had been comprised of individuals who saw their economic rights violated with poor working conditions as well as their sense of dignity violated with the belief that business growth trumped over all.  Steffens' study of the conditions in American cities within industrialization allowed America to understand that conditions in the urban center of America have to be understood, rectified, and enhanced through positive intervention in order for America to fulfill the promises and possibilities intrinsic to it.