The head and neck region is a marvel of anatomic complexity and it encompasses a broad array of subsites, each with its own architectural nuances. This histologic richness begets a commensurate diversity of disease. Advances in our understanding of the genetic and epigenetic alterations that underlie many of these tumors have not only refined their classification, but also reshaped our approaches to diagnosis, prognosis, and therapy. This Fascicle reflects these scientific and diagnostic evolutions. Departing from prior editions this volume is organized by anatomic subsite. Each chapter delves into the neoplastic conditions and key differential diagnoses germane to a specific location. This anatomic framework is intended to provide readers with a more practical and intuitive means of navigating the field. This Fascicle serves as a useful companion—equal parts atlas, reference, and diagnostic confidant—for pathologists encountering the intricate, fascinating, and occasionally exasperating world of head and neck pathology.