In both clinical and research settings, neuropsychologists provide a unique perspective on the brain–behavior relationship. Their assessments are rooted in neuroscience and psychology, capturing subtle changes in cognition that often signal early neurodegenerative disease or the cognitive aftermath of neurological trauma. Neuropsychologists contribute to the longitudinal monitoring of conditions such as Parkinson’s disease, multiple sclerosis, and brain tumors, enabling more precise evaluations of progression and treatment efficacy. Their work also supports neurorehabilitation programs, as cognitive profiles guide therapeutic goals and track patient improvement. Beyond clinical practice, neuropsychologists lead investigations into how social, emotional, and environmental factors interact with neurocognition. This interdisciplinary scope places them at the center of efforts to understand cognitive resilience and vulnerability. Their expertise is especially valuable in differentiating organic cognitive decline from psychiatric presentations such as depression or anxiety. In forensic settings, neuropsychologists offer expert testimony and cognitive evaluations in legal proceedings involving competency or injury. With the growing emphasis on brain health in aging populations, the role of neuropsychologists has expanded rapidly. Their detailed, functional understanding of the human brain continues to shape approaches to neurological disease management, cognitive recovery, and educational accommodations across diverse populations.