chapter  2
Part 2 LAND USE REGULATION
Pages 80

Planning arose from the need to protect property. Following the tradition of nuisance law, the favored technique since the 1920s has been zoning: the division of a local government area into districts which are subject to differing regulations regarding the use of land and the height and bulk of buildings that are permitted. A major reason for the introduction of zoning was the huge influx of immigrants into the cities (18 million in the thirty years from 1890 to 1920) and their impact on middle-and upper-class neighborhoods.