What was the author's purpose in Twenty Years at Hull House?

In this book, Jane Addams was trying to get her readers to
understand the social and economic problems faced by the poor in Chicago (and, by
extension, in the rest of the country).

Jane Addams was one
of the founders of the settlement house movement during the Progressive Era.  Settlement
houses were set up by middle class women like Addams as a way to help poor, usually
immigrant, people deal with their problems and (hopefully) improve their lives.  Addams
wrote this book to publicize the problems that her clientele faced so that people would
push the government to enact progressive legislation that would help the
poor.