Volume 1 reviews the basic mechanisms underlying visual depth perception. It starts with a review of the history of investigations of visual depth perception, from the ancient Greeks to the early 20th century. A review of the structure and physiology of the primate visual system is followed by a review of the evolution of visual systems and of the development of the mammalian visual system with an emphasis on neural plasticity. The development of perceptual functions, especially depth perception, in human infants is then reviewed. These chapters provide a foundation for a review of the effects of early visual deprivation on the development of amblyopia and of defects in visual depth perception. Volume 1 ends with reviews of the accommodation mechanism of the human eye and vergence eye movements.