Lewis Hine

Texas orphans picking cotton, 1913 (Lewis Hine)

(Wikipedia) Lewis Wickes Hine (September 26, 1874 – November 3, 1940) was an American sociologist and photographer. Hine used his camera as a tool for social reform. His photographs were instrumental in changing child labor laws in the United States.
... Hine's work for the NCLC was often dangerous. As a photographer, he was frequently threatened with violence or even death by factory police and foremen. At the time, the immorality of child labor was meant to be hidden from the public. Photography was not only prohibited but also posed a serious threat to the industry.
To gain entry to the mills, mines and factories, Hine was forced to assume many guises. At times he was a fire inspector, postcard vendor, bible salesman, or even an industrial photographer making a record of factory machinery. Continued