These days, most people hearing the name “John Snow” will think of the character Jon Snow from HBO’s Game of Thrones, a hugely successful series based on the books by George R. R. Martin. Many of the 6 million+ viewers of this fantasy series may not know that there was another John Snow, perhaps one without the coal-black curls and swarthy good looks, but a man who changed the world of medicine and saved millions of lives. What does a fictional hero who wields a magical sword to destroy the undead atop a 700-foot wall of ice have to do with a Victorian-era physician who wielded nothing heavier than a fountain pen as he collected thousands of data points in a 1-square-mile neighborhood of London? The answer may surprise you!
