This book, the proceedings of the Falk Symposium No. 146 ?Gut-Liver Interactions: Basic and Clinical Concepts?, held in Innsbruck, Austria, on March 11-12, 2005, brings together gastroenterologists and hepatologists both at a clinical and a basic scientific level. Topics have been structured in such a way to be of interest to both clinicians and basic scientists. The main focus of the book is to highlight the role of the immune system in gut and liver diseases and potential interactions of the gut and the liver respectively. Special emphasis is based on the importance of the gut flora in intestinal and also in liver diseases. The role of NOD2 is one of the very best examples demonstrating the importance, not only in inflammatory bowel diseases, but also diseases well beyond this barrier.Such intense interactions between gastroenterologists and hepatologists, as shown through this book, might boost and stimulate scientific ideas and research in other unexpected areas.