The opportunity to continue to promote the extraordinary educational value of the exquisite art of Dr. Frank Netter in a state-of-the-art update of this classic series has been an honor for me and my esteemed associate editors. Netter's images have brought insightful value to students for over 6 decades and have now been updated and enhanced to benefit future generations of students. This updated edition of Digestrve System has been rewritten and renewed to include cutting-edge science and state-of-the-art endoscopic， pathologic， and radiographic images， along with Netter's ageless drawings and images that provide insights that foster students' and practitioners' understanding of the anatomy， physiology， and pathophysiology of all eight regions that make up the fascinating and complex digestive system.
　　Frank Netter， MD， described by the Saturday Evening Post as the \"Michelangelo of Medicine，\" continues to be an icon in medical education. The insightful imagery of his medical illustrations provides value for students at all levels of experience who seek insights into the structure and function of digestion in ways that few other texts have in the history of medical education. His vision for these texts-integrating factual information with visual aids-provides unparalleled insights. While born at the onset of the twentieth century， his background mimics many modern medical studentsbeginning his education in the arts before becoming a scientist. By following his mother's wishes to move beyond art and into medicine， Frank Netter used his passion and brush to communicate the science and the art of medicine in unparalleled ways. In distinction to anatomy texts that offer images of structure only， Netters paintings also brought incredible insights into the pathophysiology of disease. Just as important， in ways unsurpassed by any other text， he and his dedicated disciples have illustrated how patients are affected by the suffering caused by disease. In all three of these revised parts of Digestive System， new artists， committed to the style and value of Dr. Netter's illustrations and led by Carlos Machado， MD， have modernized both the science and the art of his illustrations in all aspects of the digestive system.
　　This update of the digestive system's anatomy and disease has taken a new approach to communicate the complexity and integrated beauty of this fascinating organ system. The classic images Dr. Netter drew were preserved whenever possible and altered only as necessary Dozens of modern radiographic and endoscopic images have been added to all sections in all volumes. The first section in both Parts I and II summarizes shared aspects of the digestive system. Each subsequent section is dedicated to a specific organ and reviews normal anatomy and physiology， pathology， pathophysiology， and disease presentation and treatment.
　　Each section has been written by authors who were chosen for their dedication to teaching the fascinating aspects of the digestive system. I had the honor of choosing incredibly distinguished associate editors with whom I have had the pleasure of working throughout my career. In each case they have published expertise in their respective organ system and have demonstrated their commitment to and sHll in medical education. Their knowledge and insights bring updated scientific understanding of disease mechanisms and current treatments that will convey understanding of the largest and most complex organ system that is unparalleled by other texts. In each section， Dr. Peter Ward updated each of the subsections on normal anatomy and physiology. He has worked hard to preserve the original pictures of Dr. Netter while ensuring the accuracy of the text based on current terminology and science.
　　In Part I of this three-part set I sought to provide insights and an overview of the upper digestive tract. Michele Young， MD， associate chief of gastroenterology at the University of Arizona's Veterans Administrative Hospital in Phoenix， has written the first organ-focused chapter on the complex anatomy， physiology， and pathophysiology of pharyngeal and upper esophageal funcoons. New insights into imaging and physiologic understanding of the complexities of swallowing are provided. David A Katzka， MD， distinguished professor of medicine at the Mayo Clinic， revised the section on the esophagus， and is clearly one of the world's authorities on the topic. New insights into diseases that are common today but were not known at the time of the first edition， including Barrett's esophagus and eosinophilic esophagus， are beautifully illustrated and discussed. Part I closes with a section by Henry Parkman， MD， a renowned gastric physiologist and physician from Temple University Dr. Parkman brings a special new focus on the neurophysiology and electrical physiology of normal gastric function and disease.
　　I review common anatomic， physiologic， and clinical aspects of intestinal disorders in Section 1 of Part 2. In Section 2， Dr. Missale Solomon offers a beautifully written treatment of normal and abnormal disorders of the primary digestive organ， the small intestine. In Section 3， one of modern gastroenterology's eminent educators and Dean at the University of Connecticut， Suzi Rose， MD， discusses the colon.