In his text, Behavioral Neurology of White Matter, Filley focuses our attention on the role of white matter in neurobehavioral functioning. He makes the point that much of clinical neuroscience, including neuropsychology and behavioral neurology, has focused on cognitive correlates of cortical lesions and disorders. Historically in neuropsychology, we have acknowledged the role of white matter more typically in vague terms of connecting pathways, but there has been a decided emphasis on cortical and subcortical gray matter regions as “where the action is.” Filley's insightful writing clearly supports his proposal that “the mind depends as much on the white matter as on its gray counterpart.