The Man Slept in This Cellar for Four Years

Jacob August Riis was an American photographer and journalist who documented the living conditions of poor immigrants and working-class families in New York City's tenement districts during the 1880s and 1890s. His use of flash photography, then a novel technique, illuminated interiors previously hidden from public view, transforming social documentary into a tool for reform. Riis's photographs accompanied his written investigations and were collected in the 1890 book How the Other Half Lives, which exposed overcrowding, disease, and child labor to middle-class audiences. His work established photography as a vehicle for social advocacy and shaped early twentieth-century progressive reform efforts.