The historical associations between bacteria and peptic ulcer disease; the bacterial flora of the stomach; taxonomy of Campylobacter pylori; survival and growth of Campylobacter pylori; Campylobacter pylori - biochemical characteristics; Campylobacter pylori - enzymes; the ultrastructure of Camplyobacter pylori; Campylobacter pylori - detection and culture; detection of Campylobacter pylori by histology; detection of Campylobacter pylori by the biopsy urease test; the serology of Campylobacter pylori infections; detection of Campylobacter pylori by the 14C breath test; detection of Campylobacter pylori by the 13C-urea breath test; Campylobacter pylori, duedenitis and duodenal ulceration; Campylobacter pylori, gastric ulceration and post-operative stomach; Campylobacter pylori and gastric cancer.