Rett disorder is a devastating neurodevelopmental disorder that most exclusively affects girls, and is the second most common cause of severe intellectual disability in females after Down syndrome. Its many manifestations include epilepsy, scoliosis, nutritional difficulties, and disorders ofmood and development. This new paperback edition of Rett Disorder and the Developing Brain provides an up-to-date account of current research into the disorder. The first section presents clinical signs and the latest research into the genetic, neuro-anatomical and neurochemical aspects of Rett disorder. The second section moves on to deal with the neurophysiological research, concentrating on the autonomic system, which is deeply implicated in the diseasemechanisms. The final section examines the behavioural and psychological features and discusses issues relating to communication. The chapters are written by a distinguished, international team of experts, all currently active in research. The contributions bring our understanding of Rett disorderright up-to-date, as the study of the condition moves from an era of description into a time when there are real possibilities for beneficial interventions.