The basis of this book is a ten-lecture course on the control of gastrointesti nal motility given each year to the final year undergraduate students in Physiology at Sheffield University. A naive thought led me to believe that the conversion of my lecture notes into the present book would be a relatively easy task. I now know differently. As there is no equivalent undergraduate course elsewhere that I know of, it would be dishonest of me to claim this book to be an undergraduate text. The comprehensive way in which I have dealt with the subject, together with the inclusion of the most up-to-date material, make the book more relevant to postgraduate students of physiology, medicine and related sciences who require an introduction to the field of gastrointestinal motility and its control. I have, however, attempted to present the current concepts on the physiological mechanisms regulating motility in a way which under graduates, as well as postgraduates, will find readable, informative and, hopefully, enjoyable."