Dr Atkinson's work has grown out of a deep satisfaction with the state of theorising in child language development. Critical analysis of superficially attractive theories showed that they had no real explanatory power. Yet no coherent framework had been proposed for evaluating theorising in this area. A central tenet of this volume is that theories of language development should be relatable to some general view of human development and, on this basis, Dr Atkinson presents a number of conditions that any adequate theory of language development should satisfy. The major theories in most areas of language acquisition, in particular work in semantic, syntactic and functional development, are then systematically examined in the light of these conditions and found wanting. In a final chapter, the author relates his work to recent studies in the formal theory of learnability. This scholarly critique should be read by anyone with a serious interest in the study of child language development and will undoubtedly have a singular impact on the field.