The third edition has been extensively revised and expanded to do justice to the rapid advances in MR technology, molecular biochemistry, and genetics and the discovery of new disease entities with prominent white matter involvement. Forty chapters have been added, and the number of illustrations has risen considerably. The ability to confirm the presence of genetic alterations in a number of disorders allows more advantageous presentation of the phenotypic variation as expressed in different MR patterns. Wider coverage is given to white matter disorders, hereditary and acquired, in the adult population.