"The paradigm of a journey from observation to hypothesis testing and then onward to fulfil Koch's postulates. The discovery 40 years ago of the Helicobacter Pylori organism was a paradigm shift in many ways. Perhaps most importantly as it indicated that the host and the organism have a complex interaction which can lead to disease, not only chronic infection, autoimmunity, but also several forms of cancer. As an adjunctive benefit it showed that we should question any disease causation assumptions which are not evidence based, Stress as a cause of ulcers being the best example. The journey was long in that it took time to assemble the epidemiological, bacteriological, clinical, oncological teams. The result was, and still is, to provide the only cure for a condition in gastroenterology, peptic ulcer disease. The benefits also included alleviation of dyspepsia, cures of low grade gastric MALTOMA's and prevention of epithelial tumors of the gastric antrum. This discovery has spawned new interest in fields of research outside the infection inflammation cancer sequence, including probiotics, antibiotic resistance, and modulation of host-bacterial interactions. As I reflect on my career's narrative above, I am therefore glad to see such a large array of multidisciplinary experts working together in this endeavour of Gastrointestinal Oncology: A Critical Multidisciplinary Team Approach. Cancers of the gastrointestinal tract (GIT) encompassing esophagus, stomach and colorectum make up a significant proportion of cancers diagnosed worldwide and contribute to a considerable burden of disability-adjusted life years and years of life lost. (Kocarnik et al., 2022) The increase of GIT malignancies has been linearly associated with the human development index (HDI), likely due to the adoption of an affluent lifestyle with an increase in the consumption of processed meat, fast food, sedentary lifestyle, smoking, and increasing alcohol consumption. Obesity has become a worldwide pandemic and has been linked to the development of GIT cancers through multiple genetic and epigenetic microenvironment changes. Excess adipokines in obesity mediate a state of chronic inflammation resulting in the activation of multiple pathways that promote carcinogenesis. The understanding of the epidemiology and predisposing factors to GIT cancers is crucial in the development of early detection strategies. Screening efforts such as colonoscopy has reduced the burden of CRC worldwide. Similarly, screening of gastric cancers which has been adopted in Japan and Korea has reduced the numbers as well as improved the survival of gastric cancer. In this chapter, we will discuss the epidemiology, global time trends, burden of disease, risk factors of esophageal, gastric and intestinal cancer and strategies to reduce the incidence of these malignancies"-- Provided by publisher.