“The Columbian Exchange, as Crosby called it, is the reason there are tomatoes in Italy, oranges in the United States, chocolates in Switzerland, and chili peppers in Thailand. To ecologists, the Columbian Exchange is arguably the most important event since the death of dinosaurs.”

This quote gets at the heart of Mann’s thesis that the Columbian Exchange paved the way for the homogenized and globally connected culture today. Mann’s book shows the many pathways of change that occurred because of the Columbian Exchange.

“Colón and his crew did not voyage alone. They were accompanied by a menagerie of insects, plants, mammals, and microorganisms.”

One of the major themes of this work reveals the interconnectedness of trade with several other historical outcomes. The voyagers changed the landscapes of the places they visited forever because of what they brought with them and the practices they established. In particular, the diseases they carried with them eradicated a great number of Indigenous peoples.

“The Columbian Exchange had such far-reaching effects that some biologists now say that Colón’s voyages marked the beginning of a new biological era: the Homogenocene.”

Mann calls this “a thesis of this book” (p. 23). He claims that the arrival of Columbus in the Americas and the subsequent trade and travel changed the evolution of the entire planet, ushering in a new evolutionary era.