The ghost map - Steven Johnson

The triumph of twentieth-century metropolitan life is, in a real sense, the triumph of one image over the other: the dark ritual of deadly epidemics replaced by the convivial exchanges of strangers from different backgrounds sharing ideas on the sidewalk.
It is strange to have read this book at this time, when, for the first time in 100 years, this triumph is challenged. When I started reading the world was still sharing ideas on the sidewalk, the virus seemed far away. Outbreaks had a ominous peamble, too. Newspapers would track the disease's progress through the harbours and trading towns of Europe, as it marched relentlessly across the continent. And so we did, track the corona virus, from China to Italy to the first people getting it in my country, the Netherlands. When I ended the world was in lockdown, not a pumphandle to be switched off.
I am impressed by the investigators in the book, who did not only come with the first solid theory of how cholera spread, but did this with a lot of inventive and for the days new techniques in statistics, investigations and mapmaking, from door to door interview investigations to the ghost map.
There were a lot of small sidesteps in the book I enjoyed and made me realize things I did not know, like the way the population growth of the 19th century and the drinking of tea coincided or a letter posted at nine a.m. would reliably find its way to its recipient across town by noon.