Jane Jacobs turns the story of agriculture upside down.
The most popular story is that stone-age people lived in small groups.
Agriculture led to villages which led to towns which led to cities.
Jacobs, however, reminds us that agriculture depends on tools and chemicals produced in cities, that
the most urbanized countries have the highest production of food, and that
cities represent the richest food markets.
Everything that helps agriculture develop is made in cities.
First agriculture developed in and around the city and then it spread to
Cities invent and reinvent rural economy.
Jacobs therefore thinks that permanent settlements were widespread in
Stone Age times, and that the people of those prehistoric times were
manufacturers, traders and builders, not just hunters and gatherers.
Cities are engines of innovation. Jacobs juxtaposes the economy of Manchester in the 19th century with that of Birmingham. Manchester decayed rapidly but Birmingham survived. The reason is that the economy of Birmingham was much more diversified. Manchester was a monster of productivity and efficiency. Birmingham was a laboratory progressing by trial and error. The efficiency went against the exploration. Efficiency tends to kill the experimenting. Birmingham continued to create new goods and services, Manchester did not. Birmingham relied on many small investments that were more inefficient than in Manchester. Birmingham was an "impractical" city where one kind of work led inefficiently to another. Growing cities generate new problems that are solved by new goods and services.