Wednesday was the first day of the semester at UC Berkeley, where I attended the first lecture in my Visualization course. In it, the professor was obligated to mention John Snow’s 1854 map of cholera deaths near the Broad Street pump in London.

It’s a landmark work in the fields of both visualization and epidemiology. But I was still surprised when, the next day, exploring my local used bookstore, I came across The Ghost Map, a book that recounts every detail of the epidemic and Snow’s path toward discovering its means of transmission. I’m looking forward to reading about how Snow came upon the insight to use a visualization—a map, in this case—to convince others of his theory that the disease was carried in water, and that the Broad Street pump was the source of so many infections. (In case you haven’t heard the story, his visual argument was a success. The pump’s handle was removed, so the people had to look elsewhere, to uncontaminated sources, for water.)