Dorothy H. Crawford is Emeritus Professor of Medical Microbiology at the University Of Edinburgh, where she has been Assistant Principal for Public Understanding of Medicine since 2007. She was elected a Fellow of both the Royal Society of Edinburgh and the Academy of Medical Sciences in 2001, and awarded an OBE for services to medicine and higher education in 2005. Her previous books include The Invisible Enemy (OUP, 2000), Deadly Companions (OUP, 2007), and Viruses: A Very Short Introduction (OUP, 2011).