The concentric zone model is a theoretical framework used in urban sociology to describe the layout of cities. Developed by sociologist Ernest W. Burgess in the 1920s, it illustrates how urban areas expand outward from a central point, typically the downtown area. The model divides the city into five distinct zones, each with different functions and characteristics. The first zone is the central business district, followed by zones of transition, working-class housing, middle-class housing, and finally, commuter zones. This model helps explain patterns of urban land use and social stratification, highlighting how different socioeconomic groups are distributed within a city.