Research in cognitive psychology has contributed much to our understanding of reading and spelling. Most of this work has concentrated on the processes used by literate adults to comprehend and produce written language, but there is a growing interest in applying cognitive theories to the development of literacy, and to the understanding of disorders of reading and writing. Such disorders may be acquired as a consequence of a brain injury to a previously literate adult, or may be developmental, occurring in otherwise normal children. This textbook attempts to present this work to a non-specialist audience.