Perception, broadly defined, is the construction of a representation of the external world, for purposes of thinking about it and acting in it. Although we often think of perception as the processing of inputs to the sense organs, the world conveyed by the senses is ambiguous, and cognitive and sensory systems interact to interpret it. In this course, we will examine the sensory-level mechanisms involved in perception by various sensory modalities, including vision, audition, and touch. We will learn how sensory coding interacts with top-down processing based on context and prior knowledge and how perception changes with learning and development. The goals include not only imparting basic knowledge about perception, but fostering an appreciation for the beauty of perceptual systems and providing some new insights into everyday experiences.