This book explores the far-reaching implications for linguistic theory of Eleanor Rosch"s seminal work on categorization. A common assumption is that all members of a category necessarily share a common set of attributes. Rosch"s research suggest, instead that categories are definable in the first instance in terms of best examples--or "prototypes"--and that things get associated with the category on the basis of some kind of similarity with the prototype. John R. Taylor extends the prototype approach from its obvious applications to lexical semantics, opening up exciting possibilities for the study of morphology, syntax, and phonology. He explores a number of topics along the way, including the encyclopedic nature of all semantic knowledge, the redundancy of pragmatics, the phenomenon of polysemy, the processes of metonymic and metaphorical extension, and language acquisition.