Where I got the book: from the library. It's been on my TBR list for a while, but when Holly Tucker started a history and science readalong on Goodreads, I knew its moment had come.
The Ghost Map is, in part, an account of a cholera epidemic that took place in London in 1854. I say in part, because the epidemic is really a springboard for a series of discussions. In a sense, this book is the history of an idea: that a disease could be waterborne.
Back in 1854, this idea was startling, and unacceptable to most of the medical and administrative establishment. Johnson does a good job of highlighting the work of two men, John Snow (who did a lot of the thinking that led to the understanding of how the epidemic grew) and Henry Whitehead, who confronted the disease at street level, talking to the survivors and collecting much of the informal data that helped Snow test his theories.
I found it very interesting to read about the struggle that Snow had with the proponents of the "miasma theory," the prevailing wisdom of the time. Back then, people believed that diseases were spread by smells traveling through the air; I've read a lot of Dickens, so I'm well acquainted with the notion of pestilential or noxious air. The fact that this belief seems so ridiculous to us now is evidence of the inroads science has made into our lives.
I had never really thought about the seismic shift that occurred when science began to understand nature at the microscopic level. And I had never given much thought to the correlation between clean water and the expansion of cities to the multi-million-headcount levels that are normal to us today. So on the whole, The Ghost Map was a pretty enlightening book. It's written in an easy to read style, and is a page-turner in its way.
The book ends with an extensive consideration of urbanization and what it means to mankind. I'm not sure whether this enhances the central story, or detracts from it. It's interesting, in its way, but in the end it's only speculation--and speculation is endless. So the end of the book seemed, well, endless. I probably could have stopped reading at around page 217.
Still, on the whole this was an interesting book, and I'm glad I finally read it.