Savants are people who are mentally and often physically impaired but who have one dazzling talent. Cases of savants, like Christopher who is described here, are not unheard of, but have never been reported before. Despite being unable to look after himself because he has difficulty with everyday tasks, Christopher can read, write, translate and communicate in fifteen to twenty different languages. In this original, detailed and wide--ranging study, Neil Smith and Ianthi--Maria Tsimpli not only provide insight into the mind of one unique individual, but simultaneously cast light on the nature of language and thought in general. By exploiting recent developments in both linguistics and psychology the authors have made an essential contribution to the whole field of cognitive science.