Gregory Clark's A Farewell to Alms is among the books that discusses this. <https://en.wikipedia.org/wiki/A_Farewell_to_Alms https://en.wikipedia.org/wiki/A_Fa

Gregory Clark's A Farewell to Alms is among the books that discusses this. <https://en.wikipedia.org/wiki/A_Farewell_to_Alms https://en.wikipedia.org/wiki/A_Farewell_to_Alms> Cities simply could not grow without net in-migration until the development of sewerage, municipal waste removal, fresh-water systems, and public health in general. Another favourite illustration, "The Conquest of Pestilence in New York City", showing the overall decline in mortality from 1800 to present: <https://1.bp.blogspot.com/-uTWEATUzgxk/TXQoTibILtI/AAAAAAAAAAM/eyirotYDmXo/s1600/2004_01_healthstat.jpg https://1.bp.blogspot.com/-uTWEATUzgxk/TXQoTibILtI/AAAAAAAAA...> From: <https://economicspsychologypolicy.blogspot.com/2011/03/conquest-of-pestilence-in-new-york-city.html https://economicspsychologypolicy.blogspot.com/2011/03/conqu...> Note that for all the vaunted advances of 20th century medicine, the needle hardly moved at all from 1920 through 1990, and mortality increased from 1950 -- 1970. There has been substantial improvement from 1990 through 2000.