Jacob Riis was a muckraking journalist. A Danish American immigrant, he went through poverty himself, and as a photo journalist he was primarily interested in bringing up the issues of poverty in his pictures. The main subject of his pictures were the awful conditions in which poor people had to live, he photographed slums, tenement houses, lodging houses in the city. His first major work published in 1889 called “How the other half lives” generated a lot of public attention. It was an illustrated account about life in the city. After the book came out NYC Police Commissioner had to close down the lodging houses that were featured in the book.