I first came across John Snow (not to be confused with Jon Snow) in an article about “Disease Detectives” in National Geographic. And then in my GCSE History course as medicine between 1700 and 1850 or so was included, he came up again.
In case you have never hear of him, he is the chap who plotted every case of cholera on a map, and realised that they were all clustered around a pump on Broad Street. He removed the handle, and the outbreak dried up. The outlying cases could be traced to people who had also drunk from that pump.
There is even a society in his honour – The John Snow Society, and I have to admit that in a statistics and research type of way I do find it interesting.