Jacob Riis (1849-1914) was born in Denmark and emigrated to America at the age of 21. After several years of poverty, he found work as a police reporter, which took him into the worst of New York's ghettos and tenements. Appalled by the conditions he found there, he began to use the primitive
new flash technology to photograph the dark places that had never before been so graphically exposed. The resulting book, How the Other Half Lives, brought...