The chief purpose of Jacob Riis’s pioneering work of photojournalism and social commentary, published in 1890, is announced in its title. It is to show one half of American society—the more prosperous, comfortable half—how the other half lives. Riis remarks that, in New York City, which is the subject of his study, the other half is now actually the other three-quarters, as there are now 37,000 tenement buildings housing over 1,200,000 people. Most upper- and middle-class New Yorkers never see the poorest areas of their own city. Although there is a great deal of description and exposition in the book, the photographs are of primary importance in making Riis’s case.

In the photograph “Typical tenement fire-escape serving as an extension of the flat: Allen Street,” for instance, Riis shows the danger as well as the squalor of living conditions in the tenements. The fire escape is so smothered with laundry as to be almost invisible, and the rickety balcony is also covered with washing set out to dry and cluttered with bottles and barrels, creating a lethal obstacle course for anyone who might have to escape from a fire (and fires, as Riis goes on to show, are all too frequent). In “Jersey Street tenements,” the crumbling buildings are patched with various makeshift arrangements of wood and wire that look as though they could give way and fall on the inhabitants at any moment. Three men perch uncomfortably on a narrow bench, while a woman holding her child has to stand.

Riis supplements these pictures with his own descriptions and anecdotes, showing the sordid and perilous nature of life in the tenements. In chapter 4, “The Down Town Back-Alleys,” he relates an incident in which he managed to set fire to a house by taking a flash-bulb picture. The paper and rags on the wall caught fire, and because Riis was “in an attic room with a dozen crooked, rickety stairs between us and the street,” he says that he despaired of getting out alive. The fire was only eventually smothered “with a vast deal of trouble.” This is just one of many instances showing that life in the tenements, apart from being poor and miserable, presents frequent dangers unimagined by more prosperous New Yorkers.

Many of Riis’s most memorable pictures are of children. In “Street Arabs in Sleeping Quarters [Church Corner],” for instance, he depicts three young boys, barefoot and dressed in filthy, ragged clothes, trying to sleep on a street corner by a grating. Several other pictures tell similar stories, and there are also haunting portraits of individual children, such as “Girl of the tenements.”

Riis includes various chapters on children, roughly divided between those which deal with homelessness and those which depict child labor—both issues that prevent the children in question from receiving an education and escaping from poverty. He describes an interview with a boy who has been taken into police custody and is in no hurry to leave, since it is much more comfortable there than where he lives. The boy is asked which church he attends and astutely replies that he has no suitable clothes for church:

“Well, where do you go to school, then?”
“I don’t go to school,” with a snort of contempt.
“Where do you buy your bread?”
“We don't buy no bread; we buy beer,” said the boy, and it was eventually the saloon that led the police as a landmark to his “home.” It was worthy of the boy. As he had said, his only bed was a heap of dirty straw on the floor, his daily diet a...