In recent years our approach to neurodevelopmental disorders has undergone extraordinary change. This has resulted from tremendous progress in various several disciplines including develomental neuroscience, behavioural and molecular genetics, and developmental neurobiology, and from the very high quality now achievable in neuroimaging and neurophysiological techniques. This publication aims to provide a concise and interdisciplinary approach to the study of the different cognitive/behavioural phenotypes encountered in a qide range of neurodevelopmental disorders. Starting from methodological, nosographic, and assessment premises, the book deals with selected disorders of a defined but still complex genetic aetiology, and concludes with a description of the neuropsychiatric disorders that are most commonly encountered during development.