Linguist Noam Chomsky maintains that the human brain has an innate language faculty, and that part of this biological endowment is a 'universal grammar', a theory of principles common to all languages. Thus, all human languages and the ways in which children learn them are remarkably similar. Chomsky's book Syntactic Structures was a turning-point in 20th-century linguistics, challenging assumptions in many areas such as philosophy, psychology and intellectual history. Heir to the Enlightenment tradition, Chomsky has introduced new perspectives on language, the creative individual and the nature of human freedom in society. Introducing Chomsky traces Chomsky's understanding of the cognitive realities involved in the use of language, and the technical apparatus needed to represent it. The book also describes Chomsky's radical critique of the institutions of power and the pathways of oppression, and his commitment to freedom and justice.