Rett Syndrome is a severe neuro-developmental disorder characterised by losses in the areas of intellectual functioning, fine and gross motor skills and communicative ability. Other features include deceleration of head growth and the development of stereotypic hand movements, occurring after a period of apparently normal development. This book examines the history of Rett Syndrome, as well as the considerable research being conducted in this particular field including a study which presents the reversal of Rett Syndrome signs in a mouse model in the laboratory of Adrian Birds. Due to the rapid progression of gene therapy and the vast interest of the global scientific community, it is probable that within a matter of years a cure can be found for individuals with Rett Syndrome.