This book is an excellent introduction to the field of child language development. Itdemonstrates the need for both a theory of language development and reliable speech andcomprehension data in child language research. As Foster-Cohen states in the preface to the book,the adoption of only a single approach, as opposed to a combination of different approaches, isunlikely to lead to a productive understanding of child language acquisition. The booksuccessfully adopts the perspectives of both the empiricist and the rationalist traditions in itstreatment of key issues.