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 'routine' histological procedures that one wonders how their signifi­ cance had escaped recognition for so long. The topics covered in this volume have been selected because they present advances of relevance to the diagnostic clinical pathologist. However, they re­ present the personal selection of the editor, and are in no way exhaustive. Many other examples of progress in our understanding of the pathophysiology of gastrointestinal diseases have been omit­ ted, either because of the confines of space or because they have been well reviewed recently in other publications. Most of the workload of the practising gastrointestinal patholo­ gist involves the diagnosis and assessment either of inflammation or of neoplasia in the alimentary tract, and this is reflected in the topics presented in this book.

Progress in the Pathology of Gastritis and Duodenitis.- Precancerous Lesions of the Gastrointestinal Tract.- A Barrett's Oesophagus.- B Gastric Dysplasia.- C Duodenal and Peri-ampullary Adenomas.- D Intra-epithelial Neoplasia in the Anal Canal and Peri-anal Area.- Gastrointestinal Biopsy Diagnosis in the Tropics.- The Gut-Associated Lymphoid Tissue and Its Tumours.- The Place of Quantitation in Diagnostic Gastrointestinal Pathology.- Topics in Colorectal Biopsy Diagnosis.- A Collagenous Colitis.- B Ischaemic Colitis.- C Intestinal Spirochaetosis.- D Biopsy Diagnosis of Hirschsprung's Disease and Related Disorders.- E Malignant Polyps - Pathological Factors Governing Clinical Management.- Prognostic Factors in Colorectal Cancer.- Polyposis Syndromes - An Update.