A series of international symposia on viral hepatitis and liver disease has been held triannially, and called the "Olympics" of this research field. Our book presents the results of the eighth of these "Olympiads" which for the first time, was held in Asia (May 1993, Tokyo). Due to the rapid progress in research on both basic and clinical aspects of viral hepatitis and liver disease, the state of the art in this field is continually being updated, and our book provides a broad and in-depth survey of current work. The major topics in our book include molecular biology of the five known hepatitis viruses (HAV, HBV, HCV, HDV, and HEV), clinical implications of genetic variants of HBV and HCV, interferon treatment of HCV-related liver disease, and worldwide epidemiology and control of viral hepatitis. New subjects not seen in previous books, such as genotypes of HCV, are also covered. Expanding knowledge about the heterogeneity of the HCV genome has revealed a great variety of genotypes as well as their association with host pathogenesis and their varying responsiveness to interferon therapy. The first promising results of efforts to develop a hepatitis C vaccine are also presented. Finally, compared with its predecessors, our book contains many more papers from Asian countries, where the prevalence of viral hepatitis and liver disease is the highest in the world.