This book is based upon 45 years of clinical and scientific experience with gastroenterology, especially the stomach. In clinical medicine, Marshall and Warren's assertion that Helicobacter pylori is the main cause of gastritis, peptic ulcer disease, and gastric cancer made an immense impact. However, although peptic ulcers now can be treated with antibiotics, drugs that inhibit gastric acid secretion, including proton pump inhibitors (PPIs), are used in up to 10% of the adult population in Western countries in the treatment of gastro-oesophageal reflux disease and dyspepsia. For a long time, PPIs were the most frequently sold drugs, which made their economic impact huge. The reduction of gastric acidity induces the release of the gastric hormone gastrin, which stimulates its target, the ECL cell, to release histamine; this subsequently augments the acid secretion from the parietal cell. Gastrin also stimulates ECL cell proliferation, and long-term hyperstimulation leads to the development of tumors. The author of this book began his studies into the role of the ECL cell in human gastric carcinomas by demonstrating ECL cell markers in gastric cancer cells. This incriminated the ECL and its main regulator, gastrin, in gastric carcinogenesis. Every condition with reduced gastric acidity including treatment with drugs inhibiting acid secretion, leads to increased gastrin and thus to a predisposition to gastric cancer. This short book provides ample evidence of the pharmaceutical industry's influence on medical science. It also highlights the lack of respect and attention that the medical world gives to a biological function like gastric acidity, which prevents microbes, including viruses and prions, from entering the body through the gut.