Ernest W. Burgess (1886-1966) along with Park established a distinctive program of urban research in the sociology department at the University of Chicago in the early twentieth century. According to Burgess the rural to urban shift has been more logical and rapid in the USA than in Europe. But how does one explain the expansion process of the cities?

Burgess developed a theory of city growth and differentiation based on the social Darwinist principles found in the work of Park. The focus of the work has been devoted to earmarking the ‘natural areas’ in the city. According to Burgess the expansion of the city is best explained by a series of concentric circles. The other general assumption that lies at the heart of his work is that the spatial order of the city is a product of and reflects the moral order. However, the diagram he presents is not as neat in real life, as complications were introduced by the lake front, the Chicago river, railroad lines as well as resistance of communities to invasion.