Prototype theory makes a crucial distinction between the central and peripheral sense of words. Geeraerts explores the implications of this model for a theory of semantic change, in the first full-scale treatment of the impact of the most recent developments in lexicological theory on the study of meaning change. He identifies structural features of the development of word meanings which follow from a prototype-theoretical model of semantic structure, and incorporates these diachronic prototypicality effects into a theory of meaning change. The author strikes a balance between theoretical exploration and diachronic description, supporting each step in the argumentation with detailed case studies which chart the semantic development of particular words, or illustrate specific mechanisms of semantic change. Thus the book provides both a theoretical model for diachronic semantics and a number of methodological strategies and representational formats that exemplify how changes of word meaning can be studied in practice.