Towards a definition of a virus; how to handle animal viruses; the structure of viruses; viral nucleic acids; the process of infection, I - attachment and penetration; the process of infection, IIA - the Baltimore classification; the process of infection, IIB: the replication of viral DNA; the process of infection, IIC - RNA synthesis by RNA viruses; the process of infection, IID - RNA viruses with a DNA intermediate and vice versa; the process of infection, III - the regulation of gene expression; the process of infection, IV - the assembly of viruses; lysogeny; interactions between viruses and eukaryotic cells; the immune system and interferon; virus-host interactions; vaccines and chemotherapy - the prevention and treatment of virus diseases; carcinogenesis and tumour viruses; the evolution of viruses; trends in virology; the classification and nomenclature of viruses.