The purpose of this volume is to serve as a reference manual and guide for the diagnostic and therapeutic approaches to common adult and paediatric gastrointestinal motility problems. In order to enhance the understanding of these disorders, a problem-oriented approach has been chosen, and whenever possible the authors have provided clinical case scenarios to illustrate their message. Gastrointestinal motility has evolved from an esoteric laboratory tool to a sophisticated diagnostic technique that is now widely used clinically to guide management of complex gastrointestinal problems. Today it is the most rapidly growing subspecialty within gastroenterology. Previously, many of the gastrointestinal motility problems were either ignored or attributed to a disturbance of psyche . With the growing knowledge and understanding of how gastrointestinal muscle and nerve dysfunction can cause disease, we are at the threshold of a revolution in our approach to the diagnosis and treatment of gastrointestinal motility disorders.