VERLYN KLINKENBORG has written a thoughtful article in "The New York Times" about the photographs of Joseph Riis, and how they were used to affect social change in the slums and ghettos of New York in the late 1880s.

She writes, "His pictures are a harsh, unofficial census, a record of impossible conditions in immigrant New York. On each face he photographed, there is a look of personal extinction except, that is, on the faces of children, who somehow manage to look only hardened."

She also explains how these photographs were used — in books, and as "lantern slides" in personal lectures by Riis, who mixed rough humor, spirituality, and factual reporting to make an impact on his audiences.

You can find useful links to more information about Riis, and to see or download his books which have been digitized, at his Wikipedia entry.