This document provides an introduction to pathology, outlining key figures in the field and subdivisions of pathology. It defines pathology as the study of structural, biochemical and functional changes in cells, tissues and organs that underlie disease. Pathology is broadly divided into general pathology, which deals with general disease principles, and systemic pathology, which studies diseases pertaining to specific organs and body systems. Systemic pathology includes histopathology, cytopathology, hematology, microbiology, chemical pathology, immunology, experimental pathology, geographic pathology, medical genetics, and molecular pathology.