Although central to theories of cognitive development, the concept of representation remains subtle and elusive. This collection of papers reflects a variety of individual emphases, none of which are mutually exclusive. The papers have been arranged in four groups, mainly along lines of related subject matter but also to illustrate different aspects of the development of representation. In Piaget's theory, representation is defined as "the making present of an object which is not present to the senses" (Furth 1969). Representation has both a figurative and an operative aspect. The organisation of the content of the representation (the figurative aspect) depends on the operations of thought or on the schemes co-ordinating action. This use of the term is applic­ able both to internal representations, such as visual images and to external representation, such as children's drawings. However, it presupposes no necessary relation between a mental image and a graphic representation. The first part of the book consists of papers on children's drawing. The operative aspect of representation emerges in the serial ordering problems encountered by young children who produce "tadpole" figures (Freeman Chapter 1). The figurative aspect of graphic representation is vividly illustrated by the drawings of the autistic child Nadia (Selfe Chapter 2). One further issue which emerges concerns the relation between linguistic and graphic representation.