The functional and organic alterations of the colon constitute one of the leading reasons why patients consult gastroenterologists. The irritable colon is one of the most com­ mon causes of discomfort in human beings. The organic pathology of the large bowel (malignancy and chronic inflammatory disease) contributes, particularly among Occi­ dental peoples, to discouragingly high levels of morbidity and mortality. One realizes the importance of having a thorough physiologic knowledge of the colon in order to scientifically plan the functional treatment of organic colonic dis­ eases. If we consider the large amount of material published on the physiology of the esophagus, stomach, small bowel, pancreas, and liver, we realize that the colon has been relatively neglected. The chapters in this book have been written by people who have done their utmost to alter this imbalance. I want to thank all the contributors for their generous collaboration that allows me to present in one volume virtually all the information known about the structure and function of the colon, and to record my deep graditude to Dr. Howard Spiro for his willingness to include this volume in his series. I would also like to express my sincere appreciation to Plenum Publishing Corporation for making this book possible. A spe­ cial thanks goes to Dr.