Major RevisionSection 4 of the Academy's Basic and Clinical Science Course™ (BCSC®) presents materials in 2 parts: Part I, Ophthalmic Pathology; and Part II, Intraocular Tumors. The hierarchy of the chapters in Part I moves from general to specific to help clinicians derive a differential diagnosis for a specific issue. Part II is a compilation of selected clinical aspects of importance to the general ophthalmologist – this section contains extensive discussion of intraocular tumors.Section 4 also links selected content to the online Pathology Atlas, which contains supplemental images and case studies to help enhance reader understanding. Symbols throughout the book indicate where readers can find supplemental content in the Atlas. Additionally, Section 4 now contains Clinical Pearls, which identify information with direct relevance to clinical practice.Chapter Two has been reformatted into a Quick-Start Guide that outlines pathology in an easy-to-follow format, provides a glossary of select pathology terminology, and contains new features, such as Key Points icons and Take Note boxes, which identify important information.Section 4 of the BCSC includes 10 activities and 11 videos. Additional educational activities, including self-assessment modules and videos, facilitate learning key concepts in ophthalmic pathology. An online Pathology Atlas provides additional images, case studies, and other resources. Both print and eBook users have access to the videos and activities.Upon completion of Section 4, readers should be able to:Describe a structured approach to understanding major ocular conditions based on hierarchical framework of topography, disease process, and differential diagnosis.List the steps for handling ocular specimens for pathologic study, including preoperative surgeon-pathologist communication and obtaining, appropriately submitting, dissecting, processing, and staining tissues.Explain the basic principles of special procedures and diagnostic testing used in ophthalmic pathology, such as immunohistochemistry, flow cytometry, and molecular genetic techniques.