We are constantly at war with microbes -- SARS, MERS, E.coli, C.difficile -- filthy little organisms that threaten our health and safety. These pathogens can be deadly, but have we gone too far? Is eliminating our exposure to microbes actually bad for us? Microbiologist Dr. Brett Finlay argues that we're entering a golden era in our understanding of microbes, and that new technologies are giving us unprecedented insights into health and disease. This lecture was presented by the Peter Wall Institute of Advanced Studies.