Free digital access available with every print purchase. See inside the book for more details.Pathologists play a particularly important role in the care of patients with persistent gastrointestinal symptoms, especially those who are immunosuppressed, suffer from immune-mediated conditions, or undergo treatment for malignancies. They must be able to focus on key features present in biopsy material in order to narrow the differential diagnosis and facilitate patient management. This atlas addresses these needs in a succinct and pragmatic fashion. It describes practical approaches to the diagnosis of inflammatory gastrointestinal disorders and provides helpful criteria to distinguish between newly recognized causes of esophagitis and gastritis.