'Seeing' happens effortlessly and yet is endlessly complex. One of the most fascinating aspects of visual perception is its stability and constancy. As we shift our gaze or move about the world, the light projected onto the retinas is constantly changing. Yet the surrounding objects appear stable in their properties. Psychologists have long been interested in constancies, exploring questions such as: How good is constancy? Is constancy a fact about how things look, or is it a product of our beliefs and judgments about how things look? How can the contents of visual experience be studied...