Christopher Columbus set out to end the world. He said so in writing, at length, with scriptural citations.

He believed his voyages had been foretold by the prophets. He believed the gold of the Indies would finance the recovery of Jerusalem, without which the last act of history could not begin. He calculated that the world had roughly a century and a half left to run, and he signed his name Christoferens, the Christ-bearer, in a private cipher of triangles and dots. He was wrong about the circumference of the Earth, having read an Arabic mile as a Roman one and shrunk the planet by a quarter. He was wrong about its shape, deciding late in life that it swelled toward a summit on which the earthly paradise sat waiting. He was wrong about where he had landed, and he died still wrong about it. He was right about only one thing, and it was the thing he understood least: an apocalypse did follow him. It simply belonged to other people.

This book gives half its length to the man, because the man is the only part of the story that could have gone otherwise. The Atlantic was going to be crossed. Half a dozen rivals were already circling it, and one of them had a better route around Africa. What was not written in advance was the temperament that turned a landfall into a tribute system enforced with severed hands, the contract that made a hemisphere a family franchise litigated for a century, and the printed letter that outran the ships and turned a lucky accident into a scheduled service.

The second half follows what came through the door he wedged open. Pathogens that had waited fifteen thousand years for an introduction. Colonial institutions that took a biological catastrophe and multiplied it. A collapse so vast that the forests grew back over the abandoned fields, pulled carbon out of the air, and left a signature in Antarctic ice that we are still arguing about.