Pretty good. An interesting report on the big Cholera epidemic of 1854, including the misadventures that surrounded the decoding of its causes (and the big win – discrediting the “miasma” theory of its spread). Johnson writes as engagingly as ever, and does a nice job of discussing the some continued advantages and dangers of living in megacities. For some reason, though, the book didn’t grab me like Everything Bad is Good For You. It felt a little unfocused, like he was wondering around a bit with out a map. Oh, and the endnotes with only backreferences instead of forward references from the text seems like a really weird practice. Still, entertaining and enlightening and worth reading.

Wow! This is an awe-inspiring book. Much more than just a thorough investigation into the history of a cholera epidemic in London in the 19th century, it’s a meditation on the nature of cities and networks, on how global knowledge is dependent on local knowledge. This is a really difficult book to summarise because it’s chock-full of content, and really cool metaphors that stretch your brain.

For example, I never thought of our teeth being an example of waste recycling. Yet in a way that’s what they are, as Johnson points out. All nucleated organisms produce calcium as a byproduct. Sometime in the Cambrian age our bodies began using this calcium to make shells, skeletons, teeth, etc.

Johnson traces the history of the terrible cholera epidemic of 1854 in London, when hundreds of people died in the space of a week. An entire neighbourhood was decimated. John Snow, a physician, and Reverend Henry Whitehead, a young curate, showed that cholera was not due to miasma, the prevailing theory of the time that thought that cholera was passed through bad smells, but through the water. The book traces the epidemic as it unfolded as well as a history of cholera and public health.

Interesting and ironic point: the Board of Public Health in London was actually making Londoners sicker by engineering sewers so they poured into the Thames and made it a stinker of a river. Snow’s and Whitehead’s work were the first scientific beginnings for public health and thereafter the sewers were re-designed to flush the waste out to sea.

I especially liked the discussion of why Snow and Whitehead didn’t succumb to the conventional thinking of the time, and why almost everyone else did – I think it was an interesting study in the psychology of herd thinking and iconoclasm.

Johnson winds up with a meditation on how Snow and Whitehead made the modern city possible in a way, and also in how they were made the way they were through their lives in the city. He points out that it was their intimate local knowledge of the area where the epidemic broke out that enabled them to trace the clues that confirmed the waterborne theory of cholera.

He winds up with an exploration of whether urbanism will continue to be viable, which I didn’t find as interesting as the rest of the book, but oh well. Johnson has also started a new initiative called outside.in that sort of crystallises the thinking in his book, in trying to tie together local conversations and local events in a single website on the web (haven’t actually checked it out but that’s what I believe it is).

Overall a really worthwhile book to spend a few hours with.