Though the aetiology and pathogenesis of inflammatory bowel diseases (ulcerative colitis, Crohn's disease) remain obscure, substantial progress has been made in the understanding of these challenging disorders since the first edition of "Inflammatory Bowel Diseases" in 1983. Scientific advances include characterization of the nature of the intestinal inflammatory reaction, delineation of the varied immunological events, and the application of numerous basic scientific disciplines (including biochemistry, pharmacology, cell biology, gastrointestinal neuroendocrinology, immunology, genetics, and molecular biology) to the investigation of inflammatory bowel diseases.;In addition to careful clinical observation, clinical progress includes expanding epidemiological and familial studies, documentation of the clinical complexities of inflammatory bowel disease, assessment of the cancer risk, and such therapeutic advances as improved nutritional support, the use of elemental diets in Crohn's d