This extensive volume began as a short course primarily geared toward toxicologists who want to expand their understanding of toxicologic pathology in order to be better study directors while also proving to be of great interest to other drug development scientists and regulatory reviewers. The overall goal is to help non-pathologists understand, contextualize, and communicate the pathology data and interpretations from the study pathologist in a practical and usable format. Within the book, readers will find an overview of general pathology concepts that include fundamental vocabulary and the basics of pathophysiological processes, along with numerous chapters devoted to pathology in specific organ systems as well as topics such as biomarkers, correlation of clinical pathology endpoints (chemistry and hematology) with microscopic changes, and well-known pathology findings for classes of toxic substances.