There has been a growing interest in toxicologic pathology, especially as related to its impact on the safety assessment of pharmaceuticals and chemicals, and in drug development. Thus, there is a growing need for an Illustrated Dictionary of Toxicology Pathology and Safety Science (IDTP) that this dictionary aims to fill. The language of toxicologic pathology may be less familiar to a broad range of safety scientists, especially those involved in the safety evaluation of pharmaceuticals and chemicals. The IDTP format provides the brevity and clarity that the user is not likely to receive in a textbook, even if adequately indexed. With the inclusion of descriptions for terms used in toxicology, drug metabolism/pharmacokinetics, and regulatory science, the scope of the IDTP is considerably broadened and decidedly unique in its appeal to all safety scientists. With over 800 photos and illustrations to provide visual context,* an important aim of the IDTP is to present pathological changes as reference examples for terminology, nomenclature, and term descriptions for the entry entry-level as well as seasoned toxicologic pathologist. It will also aid students and non-pathology specialists such as study directors, senior toxicology report reviewers, scientific management of contract research organizations, regulatory agencies, and drug development companies to better understand the biological significance of tissue changes. The IDTP provides a single reference volume for these users to further their understanding and appreciation of biologically significant pathology findings. The IDTP consists of four major areas: 1. A-Z Dictionary of Pathology encompassing all organ systems, together with relevant non-pathology terms supported by references in "For Further Reading" sections. 2. Appendix 1: An Overviews of Drug Development, Nonclinical Safety & Toxicologic Pathology, and Important/Special Topics. 3. Appendix 2: Diagnostic Criteria of for Proliferative Proliferative Lesions in Rodents (Rat and Mouse) and Selected Non-Rodent Laboratory Species containing illustrations with detailed references and links to source material. 4) Appendix 3: Mini-Atlas of Organ System Anatomy and Histology to help re-acquaint the non-pathologist safety scientist with many normal anatomical structures. The editors and contributing scientists (board-certified veterinary pathologists, board-certified toxicologists, allied health safety scientists, health regulatory representatives) have experience from bench-level pathology and toxicology to managing global preclinical safety units in leading pharmaceutical companies. They have considerable experience mentoring pharmaceutical industry project team members, interacting with industry clinicians and representatives of decision-making bodies within the industry, as well as with global health authorities, such as the FDA and EMA. These activities convinced them of the necessity for and usefulness of the IDTP. As experts in their field, they have undertaken the hard work of writing and compiling the information, making the IDTP an exceptional, go-to reference. *Illustrations Editor: Gregory Argentieri