Compared to many languages, English has relatively fixed word order, but the ordering among phrases following the verb exhibits a good deal of variation. This monograph explores factors that influence the choice among possible orders of postverbal elements, testing hypotheses using a combination of corpus studies and psycholinguistic experiments. Wasow's final chapters explore how studies of language use bear on issues in linguistic theory, with attention to the roles of quantitative data and Chomsky's arguments against the use of statistics and probability in linguistics.