Despite substantial advances in developing treatments for the serious illnesses that affect people worldwide, there remains a tremendous unmet need in the treatment of complex neurologic diseases, including neuropsychiatric and neurodegenerative disorders. Chief among the challenges that have hindered the development of therapeutics for central nervous system (CNS) disorders is the blood?brain barrier (BBB). The Forum on Neuroscience and Nervous System Disorders of the National Academies of Sciences, Engineering, and Medicine convened a workshop to explore the challenges associated with the BBB that have thus far stymied development of CNS drugs, examine new technologies that could address these challenges, and highlight potential opportunities for moving the field forward. This publication summarizes the presentations and discussions from the workshop.