Perceptual Constancy examines a group of long-standing problems in the field of perception and provides a review of the fundamentals of the problems and their solutions. Experts in several different fields--including computational vision, physiology, neuropsychology, psychophysics and comparative psychology--present their approaches to some of the fundamental problems of perception: How does the brain extract a stable world from an ever changing retinal input? How do we achieve color constancy despite changes in the wavelength content of daylight? How do we recognize objects from different viewpoints? And how do we know the sizes of those objects? The volume is divided into three sections. The first describes color constancy, the second examines size, shape and speed, and the third section is on perceptual inconstancies.