A fundamental requirement of everyday life is that of encoding and remembering successfully the locations of objects, landmarks or buildings in space. This function is achieved by structuring spatial information in systems of co-ordinates. It is often argued that a person's, or an animal's, spatial memories are summarised in a cognitive map. There are two main categories for classifying spatial reference systems. One is the egocentric frame of reference which specifies location and orientation with respect to the organism and include eye, head and body co-ordinates. Allocentric frames of reference specify location and orientation with respect to elements and features of the environment independently of the viewer's position. This book presents and reviews important data on spatial memory.