The Ides of John Snow` marks a significant milestone in epidemiology, as it highlights the pioneering work of John Snow in mapping the 1854 cholera outbreak in Soho, London. By employing a dot map to illustrate the concentration of cases around a public water pump, Snow was able to demonstrate the connection between contaminated water sources and increased incidence of cholera, laying the groundwork for visual analysis using maps in epidemiology. This innovative approach utilized cartographic methods not only to depict clusters but also to analyze geographically dependent phenomena, making it a groundbreaking achievement in the field. To celebrate John Snow's birthday, there is an offer available, including a 20% perpetual discount on all new John Snow plans with code "happybdaymrjohnsnow".