This Special Issue of the Australian Dental Journal coincides with an unprecedented health event in the 21st century: the COVID-19 pandemic. Given the social and economic consequences of the disease, the vivid debate about the most effective public health measures to tackle the epidemic and the global spread of the epidemic,1 people worldwide are becoming familiar with words such as ‘epidemiology’, ‘epidemic curve’, ‘fatality rate’, ‘surveillance systems’ ‘prediction’, ‘modelling’, among other. However, what is epidemiology?