In this extraordinarily original and profound work, Noam Chomsky discusses themes in the study of language and mind since the end of the sixteenth century in order to explain the motivations and methods that underlie his work in linguistics, the science of mind, and even politics. This edition includes a new and specially written introduction by James McGilvray, contextualising the work for the twenty-first century. It has been made more accessible to a larger audience; all the French and German in the original edition has been translated, and the notes and bibliography have been brought up to date. The relationship between the original edition (published in 1966) and contemporary biolinguistic work is also explained. This challenging volume is an important contribution to the study of language and mind, and to the history of these studies since the end of the sixteenth century.