Jacob August Riis (May 3, 1849 – May 26, 1914) was a Danish American social reformer, "muckraking" journalist and social documentary photographer. He is known for using his photographic and journalistic talents to help the impoverished in New York City; those impoverished New Yorkers were the subject of most of his prolific writings and photography. He endorsed the implementation of "model tenements" in New York with the help of humanitarian Lawrence Veiller.