Private Buffoon has an interesting post about the history of cholera and how Dr. John Snow‘s study of it in 1850’s London led to our modern-day understanding of epidemiology.
I read a great book a while back about this called The Ghost Map, by Steven Johnson. It’s a fascinating book, though I would caution against reading it when you’ve just eaten, or are about to eat.
Most of the book is about the Broad street cholera outbreak, but the last chapter is a philosophical rumination on the structure of cities and city life. Both parts make for good reading. Just be aware that the title of his post applies to much of it.