In the past twenty-five years there has been an explosion in research on the development of perception. This research has produced discoveries at multiple levels - ecological analyses of the information available for perception, models of representation and process, and improved understanding of biological mechanisms. In this comprehensive treatment of infant perception, Philip Kellman and Martha Arterberry bring together work at these multiple levels to produce a new picture of perception's origins. The emphasis is on perceptual knowledge - how one comes to perceive the world; what information, processes, and mechanisms produce this knowledge; and how perceptual processes change over time. They examine early perception in various domains, such as object, space, motion, intermodal, and speech perception, and attempt to discover the starting points and paths of development of each. By focusing on individual experiments, they also give the reader a view of how research is conducted, including the interplay of data and theory.