Behavioral neurology and neurocognitive disorders encompass a broad spectrum of clinical syndromes that involve cognition, behavior, and higher cortical function. Accurate diagnosis is often complicated by overlapping symptom profiles, subtle initial presentations, and the interplay between neurologic, psychiatric, and systemic medical conditions. This chapter provides a comprehensive yet high-yield review of common and high-stakes disorders including delirium, Alzheimer’s disease and other causes of dementia, traumatic brain injury, functional neurologic syndromes, pediatric neurodevelopmental disorders, and rapidly progressive dementias. Emphasis is placed on recognizing key clinical presentations and neuropsychological profiles, correlating imaging and other biomarkers, applying diagnostic criteria where applicable, and decision-making in clinical management.