“The bustling commerce of the great city has conjured up its opposite, a ghost class that somehow mimics the status markers and value calculations of the material world.”

Johnson is speaking here about the scavengers that existed in Victorian-era London, helping to deal with the city’s surplus of waste. He is speaking, as well, about the hierarchy that existed among these scavengers. Much of his project in this book is to restore visibility to these sorts of urban underclasses, whether they are the “night soil men” of Victorian-era London or the Third World shantytown dwellers of today.

“Waste recycling turns out to be a hallmark of almost all complex systems, whether the man-made ecosystems of urban life, or the microscopic economies of the cell.” 

While Johnson’s book is in a broad sense a history, it also encompasses a great deal of science, and many other forms of life besides human life. This sentence, which makes a connection between recycling and the functions of cells, is typical of the scope of this book. 

“‘There is no document of civilization that is not also a document of barbarism.’”

This is a quote from Walter Benjamin, who also provides the epigraph for this book. It refers specifically to the overcrowded pauper graves that existed in Victorian-era London and horrified many Londoners at the time. Johnson suggests that the popularity of the miasma theory—the theory that cholera was transmitted through smell, rather than through swallowing—rested in part on the superstitious revulsion that these mass graves aroused.