The primary purpose of this text is to present the underlying psychology of dyslexia to teachers who may be taking a training course on teaching children with dyslexia. Parents of dyslexic children, and teachers who have dyslexic children in their classes, should also find the book useful. The first four chapters explain the assessment process. The text grew out of psychology lectures given by Mike Thomson on one of the Dyslexia Institute's courses in Specific Learning Disabilities. Tables and diagrams are provided in the text wherever possible. References are kept to a minimum and are not allowed to interrupt the flow of the book, and complexity for its own sake is avoided. The spotlight is firmly on the essentials.