There have been many advances in the field of gastrointestinal pa thology which are of considerable clinical significance during the 13 years since the last publication of a volume of Current Topics in Pathology devoted to this subject. Many have arisen from the app lication of new techniques of histochemistry, immunocytochemi stry, quantitative morphometry and molecular and cell biology to gastrointestinal diseases, but some, notably the recognition of the association of Campylobaeter pylori with the commonest type of chronic gastritis, have been achieved using such long established...