Jacob A. Riis (1849–1914) was a Danish-American social reformer, journalist, and photographer whose work shed critical light on the harsh realities of life among the impoverished residents of New York City's slums in the late 19th and early 20th centuries. Riis immigrated to the United States in 1870 and soon witnessed the dire conditions of immigrant life, which sparked his career as a muckraking...