This volume on the mucosal gastrointestinal pathology provides the basics and a framework to diagnose the common lesions together with a few exotic lesions that are important. In some sections the focus is on patterns of injury whereas in others, the key is paying attention to the specific type of mucosa that is injured. The authors point out a few pitfalls in each section. This volume is intended to help not only residents but also fully trained pathologists who begin to tackle an organ system that is unfamiliar to them or want to add or refresh knowledge.