This is a history of the spread and dominance of North American linguistic theory, concentrating on the influential ideas of Bloomfield and Chomsky. It gives an account of the development and continuity of three dominant ideas in linguistics: the study of formal relations can and should be separated from that of meaning; sentences are composed of linear configurations of morphemes; many aspects of grammar are determined genetically. This is an invaluable survey for all linguists wishing to trace the origins of their discipline.