Take a moment to use mental imagery to perform the following tasks: (1) decide whether an apple is more similar in shape to a banana or an orange, (2) determine how to rearrange the furniture in your bedroom to make room for a new dresser, and (3) drive home during rush hour. Although we take our ability to perform tasks such as these for granted, they raise a host of interesting questions about imagery. For instance, what is the relationship between (...) imagery and perception? What types of processes are needed to account for our ability to generate, maintain, transform, and inspect images? How do we characterize individual differences in imagery ability? What is the relation between imagery and spatial representation? What can we do with mental imagery? This essay will focus on visual imagery, because we know more about visual imagery than auditory, haptic, gustatory, or olfactory imagery. The expectation is that many principles, although not all details, of emerging theory will be applicable to imagery in other modes. (shrink)