Epidemiology is the science of counting ill people - a simple description that hides major mathematical complexity. A tremendous number of different factors combine to determine the risk that any of us might become ill, however if we could disentangle these from each other then it might be possible to target the most important factors systematically. My work is mainly on the mathematical, statistical and computational methods that we need to understand these phenomena, but I also work on other things -- please see my Google Scholar Profile; I also occasionally tweet as below: