Dr. Peter S. Spencer, a pioneering neurotoxicologist of international renown, delivered the keynote address at the 2010 Joint Scientific Symposium of the Society of Toxicologic Pathology (STP) and the International Federation of Societies of Toxicologic Pathologists (IFSTP). He has made many landmark discoveries during his four-decade career. Dr. Spencer's address communicated several fundamental principles of past and present toxicologic neuropathology research, and he also predicted future trends in the field. First, classic approaches to toxicologic neuropathology emphasized morphologic techniques such as light microscopic and ultrastructural assessment. However, neuropathology methods alone rarely reveal the mechanism(s) and etiology of neurotoxic conditions, so neurotoxicity problems are now being investigated using a multidisciplinary approach in which neuropathologic assessment is but one component of the analysis. The two primary trends for future toxicologic neuropathology investigations, in both animals and humans, will be an increased use of noninvasive neural imaging and greater preference for in situ molecular ("omic") methods, which provide functional information in a structural context. These trends will significantly enhance the ability of scientists to translate animal data to human situations, thereby improving our understanding of disease mechanisms and facilitating efforts to design new therapies for neural diseases.