.We need to see viruses, not as parasites but as symbionts forming partnerships with their hosts. That's the thesis of this book. Dr Frank Ryan begins by outlining the huge range of viruses and giving a snapshot of the diverse ways in which they operate. He goes on to describe their contribution to evolution in general and their impact upon the human genome in particular. (Apparently, without viruses there would be no placental mammals.) Widening he focus from the purely human, he discusses the crucial part they play in the regulation of the biosphere and the evidence for the argument that life on Earth began with viruses and, even suggests that viruses were critical in the development of a sense of self. The publication of this book during a global pandemic is a timely coincidence but it's also a demonstration of what a hugely important topic this is, and how necessary it has become for all of us to begin to grasp at least some of the fundamentals involved. Fascinating and hugely informative.