Nels Anderson (1889–1986) was an early American sociologist. He studied at the University of Chicago under Robert E. Park and Ernest Burgess, whose concentric zone theory was one of the earliest models developed to explain the organization of urban areas. His first publication, The Hobo (1923), was a work that helped pioneer participant observation as a research method to reveal the features of a society and was the first field-research monograph of the famed Chicago School of Sociology, marking a significant milepost in the discipline of Sociology.