When I graduated the past fall, the MPH program gave us all copies of Steven Johnson’s book about the work of John Snow in figuring out the cholera outbreak in London, Ghost Map: The Story of London’s Most Terrifying Epidemic–and How It Changed Science, Cities, and the Modern World.   I still haven’t started reading it, but it is definitely on to-do list.  Recently, while searching for information about using Prezi.com for presentations, I came across this TED talk by Johnson.   The presentation is a few years old, but a good overview of the details of the story.