The last few years have witnessed major developments in molecular biology which have had a significant impact on biomedical knowledge. As a result new concepts in cell biology have emerged, new etiologic agents have been discovered, and new drugs have become available. Furthermore, the world of mediators, cytokines, and humoral factors has enlarged considerably in a relatively short period and this has modified our views of diverse physio pathologic processes as well as opened up new therapeutic prospects. In addition, recent technologic advances have revolutionized our diagnostic methodology and have greatly enhanced the power of our therapeutic resources. All these factors have contributed to a substantial remodeling of both liver science and clinical hepatology, and these changes have generated the motivation for the production of the present book, which attempts to give an account of well-known clinical facts in the light of current thinking. It is the fruit of the coordinated work of experts from different countries in three continents. In a sense, it is a manifestation of the fact that inter national cooperation is becoming increasingly important not only in the expansion of science but also in its exposition. We hope that Hepatobiliary Diseases will be useful to both students and clinicians and that internists, gastroenterologists, and general practitioners will find in its contents a satifactory coverage of their field of interest.