Visual illusions have the capacity to both puzzle and delight: whether the swirling colours and vibrations that appear from simple concentric patterns, or surreal tricks of perspective, or the ephemeral shapes that appear as we stare into a random scattering of dots. They remind us that, contrary to the experience of everyday life, what we perceive isn't always true. In Seeing Through Illusion renowned neuropsychologist Richard Gregory explores what visual illusions can tell us about how our brains perceive the world. Looking at optical tricks and many other extraordinary phenomena, Gregory explains how scientists use them to peel back the normal processes of perception, and to reveal how the brain performs the remarkable feat of representing the real world with the kind of richness and success which we experience every day and take for granted. And these visual illusions can not only tell us about how our brain works, but they can also reveal its past. For as our nervous systems evolved, so the ways in which they perceived the visual world grew more sophisticated, moving from simple stimuli of light and darkness to the complex levels of cognition we have today. Traces of earlier stages remain buried within our brains like stratified layers, laid down through evolutionary time, and we learn how the study of different kinds of illusions helps us to glimpse these layers. Interweaving science with reflections on art and philosophy, fascinating psychological case-studies, and some amazing visual phenomena, this book reveals that we really can 'see through illusions'.