The authors of this book played an essential role in opening the gate in front of the Hungarian clinical researchers to the world. Their pioneer activities were appreciated by the University of Pécs, giving them the title of Honoris Causa Doctors. All of the authors have been working in the field of gastroenterology - in Japan, United Kingdom, the United States and Hungary. They all were aimed to cover the most important steps of their researches, and to emphasize the international scientific and friendly connection among the different nations. This volume is especially offered for the younger generation of the physicians and researchers, who can use the experiences of the older generation with the help of this book.