Stephen Greenblatt's The Swerve is a bookish nerd's wet dream. It describes how scribe monks from the Dark Ages unearthed books—and one book in particular—that eventually inspired our collective intelligence. While I appreciate the parallel between enterprising authors, their heretic fans, and human progress, Greenblatt gets a bit grandiose in his subtitle: How the World Became Modern.
The problem isn't that Greenblatt fails to corroborate his evidence. The Swerve is mind-blowingly well researched and the narrative is more engaging than most novels. He tells the story of Poggio Bracciolini, a nearly excommunicated monk who specifically sought ancient pagan literature to redistribute. In the years near the end of the Dark Ages, even Catholic monks were hopping on the humanism bandwagon. After his pope was deposed, Poggio went on a search for some of these manuscripts. What he found, on a dusty shelf in Germany, was Lucretius's poem De Rerum Natura ("On the Nature of Things"), a work that aggrandizes Epicureanism.
More than 2,000 years ago, a Greek philosopher named Epicurus was the first person to conceive of atoms, and Greenblatt says the implications of this notion were earth-shattering. (As an aside, Greenblatt even concedes, "We have by no means yet thought through them all.") The idea was that if everything were made of atoms, including the elements that were previously thought to be gods, then the world is chaos and humans are left to search for their own meaning.
It's embarrassing that millennia later, people are still terrified of what is essentially Epicureanism. That is exactly Greenblatt's shortcoming. While Poggio's translations of Lucretius's poems informed everyone from Galileo to Sir Isaac Newton, the arguments surrounding a 2,000-year-old idea are still going on and that idea is even considered radical by more than an acceptable amount of people.
What Poggio did was expand humanism in the Dark Ages. He gave people a contemporary philosophical idea that resulted in a recharged interest in ancient poetry, art, and thought. But it never went further. Greenblatt has written a stunning history of humanism in the Dark Ages, of the history of books, and an explanation of how we even know about Greek philosophy now. But what he's inadvertently written is proof that intellectual progress actually stopped around the year 1500.
If Greenblatt's greatest mistake is to forget that the world isn't modern, the reader can forgive him, because The Swerve is informative for an entirely different reason. We are in a dark age—and this time around, books are a novelty. Greenblatt gives us The Swerve; what we may get next is The Return—how a group of individuals banded together to destroy everything humanism, science, philosophy, and art worked to create. 
