This is an update of the molecular biology and clinical experience on the viruses which cause chronic hepatitis and liver carcinoma in humans and in model animals. Treatment of chronic hepatitis, reinfection after liver transplantation, in vitro replication of hepatitis B, C and D viruses, immunopathogenesis, variants of hepatitis viruses, oncogenicity, epidemiology and diagnosis and prevention are the major topics of the book. Thus, clinicians, laboratory physicians, molecular virologists and public health specialists may equally well profit from this book.