Amazon.com description: Product Description: This volume provides researchers with a coherent theoretical framework for understanding the evolutionary biology of viruses - a subject of crucial importance to scientists investigating emerging viruses, viral transmission, and geographic variations in viral epidemics. The book defines key concepts concerning the origins and relatedness of viruses, the processes producing genetic variation among viruses, and the role of virus-host interactions and natural selection in governing viral evolution. Special emphasis is on the relationship between genetic variation and natural selection, and on the evolutionary constraints imposed by the interaction of the virus with its host.