Microbial pathogenesis is the study of the mechanisms by which microbes (bacteria, viruses, protozoa, and multicellular parasites) cause infectious disease and make their hosts (humans) ill. Bacterial infections we thought were easily treatable are again a huge cause for concern with the well-publicized rise of antibiotic resistance. There are very few effective antiviral drugs and we live with the threat of epidemics such as bird flu and the outbreaks of viruses such the recent (and ongoing) Ebola crisis. Parasitic diseases such as malaria continue to pose a heavy burden in the developing world and with climate change could spread into the developed world. There is therefore an urgent need to understand microbial mechanisms, with research programmes and university courses dedicated to the subject.