Shows how science is constructing a wiring diagram of the visual path, shows about the structure of receptors in the retina, through the peanut-size clusters of cells known as the lateral geniculate bodies, to the striate cortex-- the first of many higher areas devoted to vision and the part of the brain that is now best understood. Introduces the remarkable geometric patterns that result from the surprising tendency of cells with related functions to be organized in sheets, columns, blobs, and stripes.