 Given the breadth of neuroscience so conceived, an overview of sufficient depth must restrict breadth. On the neuroscience side, this review focuses on the central nervous system and the electrical properties of neurons, particularly in the cerebral cortex. On the side of consciousness, it focuses on perceptual consciousness, with emphasis on vision. This is not because visual consciousness is more important than other forms of consciousness. Rather, the level of detail in empirical work on vision often speaks more comprehensively to the issues that we shall confront.