"Why do we know so much more than we have evidence for in certain areas, and so much less in others? In tackling these questions--Plato's and Orwell's problem--Chomsky again demonstrates his unequalled capacity to integrate vast amounts of material." David W. Lightfoot, University of Maryland "I feel that it is his most persuasive defense of the idea that the study of linguistic structure provides insight into the human mind." Frederick J. Newmeyer, University of Washington