English Summary/英文概要： The extraordinary role of viruses in evolution and how this is revolutionising biology and medicine. Dr Frank Ryan explains his decade of research at the frontiers of this new science - now called viral symbiosis and the amazing revolution that it has had in these few years. As scientists begin to look for evidence of viral involvement in more and more processes, they have discovered that they are vital in nearly every case. And with this understanding comes the possibility of manipulating the role of the viruses to help fight a huge range of diseases.