This work is a revision of Sekuler and Blake's text on sensation and perception. The third edition focuses on developments in perceptual research, blending anatomy, physiology and psychophysics to explain structure and function. New features include a revised and expanded methods section, increased coverage of speech perception, an expanded and refined touch chapter and more emphasis on cognitive issues. Chapter summaries, boxed demonstrations and computational examples are also included. This edition also contains a broadened and reorganized chapter on knowledge and perception around a simple new taxonomy of the four main models of interaction between knowledge and perception. The chapter on touch has been expanded to include important new research. An enhanced chapter on colour vision reflects new ideas on the genetics and evolution of colour vision. More than 250 new references and more than 200 new illustrations and drawings are also featured.