See also the Collections Portal of the Museum of the City of New York, where more than 1400 photographs taken by Riis are available to view online.
See also a LibriVox audio recording of the book.
Alternative link to a different full-text version…
Extract from the Introduction, 'What the fight is about' :
The slum is as old as civilization... The battle with the slum began the day civilization recognized in it her enemy. It was a losing fight until conscience joined forces with fear and…