This monographic work authored by eminent neurophysiologists will be of major interest to researchers investigating the visual system or working in behavioral neuroscience and sleep research. The book deals with the neuronal circuits of the visual thalamocortical system, the brainstem and basal forebrain modulatory systems and their neurotransmitters acting upon these circuits, and the neuronal activities in the visual thalamocortical system as changed during shifts in behavioral states of vigilance from wake to sleep. Data discussed consist of recent studies on light and electron microscopy, extra- and intracellular recordings of thalamic and cortical neurons, neurotransmitter actions, and state-dependent cellular activities in the visual system.