The field of virus evolution has developed during the past three decades from one considered by many to be esoteric and unimportant for human and agricultural health, to a major driver of our thinking about infectious diseases of plants and animals. The field has been spurred on during the past 30 years by emerging viral diseases such as HIV/AIDS, hantaviruses, SARS, MERS and Ebola, and discoveries of the quasispecies nature and potential for rapid evolution and diversification of RNA virus populations. Over time the focus of research has expanded and developed to encompass a diverse mixture...