Major Greenwood, an early 20th century English epidemiologist, said that the reason epidemiology did not progress immediately from Hippocrates’ time was that Hippocrates just considered phenomena rather than also counting them as Graunt did. In crude terms, we could say that Hippocrates was a qualitative researcher and Graunt a quantitative one. However, that said I must hasten to add that modern epidemiology embraces qualitative as well as quantitative approaches to problem-solving. This will be most apparent when we reach the section on hypothesis formulation.