My research addresses the ecology and evolution of viruses. Viruses typically have high mutation rates and can evolve extremely rapidly, yet may be the oldest of all kingdoms of life. We are still only just beginning to comprehend the extent and complexity of viral biodiversity, and to appreciate the myriad roles that viruses play as dynamic components of ecosystems. Over recent years, however, revolutionary advances in DNA sequencing and related information technologies have radically transformed the research landscape. As well as facilitating the use of genetic approaches to track viral evolution within and spread between infected hosts, explosive progress in genomics is allowing unprecedented insight into the longer-term history of viral evolution.