This new edition comprises a modern synthesis of the anatomical, physiological, and pharmacological substrate for eye movements, including current views on the reflexive and voluntary control of gaze. This synthesis is based on electrophysiological and inactivation studies in macaque, and behavioural studies in humans that incorporate functional imaging and transcranial magnetic stimulation (TMS) in normals, and clinicopathological studies in patients with neurological, visual, or vestibular disorders. Sophisticated experimental paradigms have been applied to both species to explore aspects of cognition, memory, volition, and reward. This large body of research has demonstrated the power of eye movements as experimental tools. The second part of this online resource applies this synthesis to the clinical and laboratory evaluation of patients with abnormal eye movements due to a broad range of disorders - from muscular dystrophy, and genetic disorders, to dementia, including visual and vestibular conditions.