During the decade since the publication of the first edition of this important book, there has been a rapid advancement in the techniques of genetic engineering and molecular biology. In this edition Joseph Cooper takes those advances into account and includes such topics as gene therapy, immunosuppression and new viruses of human/veterinary significance. Much new information about virus transmission is also included and the most modern systems of virus taxonomy are used to emphasise the features shared between viruses in plants, animals and bacteria. This is the only book of its type which covers viruses in all forms of life.