Alfred Marshall argues that industrial agglomerations exist in part because individuals can" learn skills from each other when they live and work in close proximity to one another. An" increasing amount of evidence suggests that the informational role of cities is a primary reason for" their...

One approach to urban areas emphasizes the existence of certain immutable relationships, such as Zipf's or Gibrat's Law. An alternative view is that urban change reflects individual responses to changing tastes or technologies. This paper examines almost 200 years of regional change in the U.S....