Between 1915 and 1940, a small faculty in the University of Chicago Department of Sociology, working with dozens of talented graduate students, intensively studied the city of Chicago . They aspired to use the approaches of social science in developing a new field of research, and they took the city as their laboratory.
Chicago was the ideal place for such an effort: in the last half of the nineteenth century it had grown from a population of 30,000 in 1850, to 1,700,000 in 1900, probably faster than any city in history. More than one-third of the population had been born abroad, in Germany, Poland, Ireland, Italy, and dozens of other countries. It had a panoply of social problems, such as prostitution, drunkenness, hoboes, and boys' gangs.
The Department of Sociology faculty sent students out into Chicago's "real world" to collect information. They employed all sorts of research methods—they refined existing ones, such as censuses, surveys and mapping, and they invented new ones, such as the personal life history.
They described and analyzed what they had seen. The Chicago sociology faculty wrote books, such as The Polish Peasant in Europe and America. Graduate students in sociology wrote dissertations, many of which became books published by the University of Chicago Press. Notable among them are The Ghetto, The Hobo, The Gang, and The Gold Coast and the Slum. Many of the books became sociological classics. Prior to this work, sociology was for the most part a combination of history and philosophy, an armchair discipline. Scholars of the Chicago School transformed it into an empirical discipline.
Significantly, the University of Chicago sociologists did not refer to themselves as a "school." The term was applied to them later, when others recognized the impact of their accomplishments as a whole.