Is there any reason to believe that reading, writing, and arithmetic involve different mechanisms of the brain? Do hearing, understanding, and expressing rely on separate brain mechanisms? These are some of the questions of interest to anyone concerned with how the brain functions that are discussed in this multiauthored book. The obvious targets for this work are child psychiatrists, psychologists, and educators. Philosophers of the mind, those interested in the question of what makes us human, will also find this book of great value. Why would general psychiatrists be interested in a book on learning disorders? Certainly, this is an area of interest to researchers, but I would argue that in addition to the obvious practical problems to be solved, there are heuristic reasons to study these problems. The confusion of DSM-IV, ICD-10, and the common parlance among "mental retardation," "pervasive developmental disorders," and the "disorders of psychological development" only mirror the confusion regarding mental function in general. This results in conflicts based on ideological and dogmatic approaches to mental functioning.