The book explains the transition from a primarily agrarian to an industrial economy to provide context for factory conditions in early 20th-century New York City. In the 18th century, goods were primarily handmade by their owners; few people had many possessions that had been produced by someone else. In the 19th century, industrialization—or the shift to mass-producing goods via assembly-line machine production—changed many things. Workers seeking jobs flooded urban centers, increasing population density and urban sprawl. City life demanded even more reliance on industry, as workers were not able to grow their own food or produce household goods. Instead of labor providing directly for people’s needs, labor now earned money, which could be exchanged for goods that would satisfy those needs; for example, food was bought instead of grown. Some economists refer to this as the alienation of workers from the products of their labor—instead of producing what was needed for the family, factory workers produced for factory owners, who paid them money for that labor.

As Marrin makes clear, one significant problem with unregulated industrialization was greed: Factory owners were motivated to maximize their profits, and with a dense population of ready workers, they were not motivated to retain or safeguard employees.