This book provides a readable and clearly articulated introduction to an important area in the broader field of Cognitive Linguistics. Taking as its starting point the categorization of colour it explores the far reaching implications of Eleanor Rosch's seminal work on prototype categorization extending it's application of prototype theory from lexical semantics to the study of morphology, syntax, and phonology. First published in 1989 the third edition of this populat text has been fully revised and updated to include recent developments in Cognitive Linguistics. It introduces basic issues in the study of word meaning, and demonstrates the viability of the prototype approach to the study of phonology, syntax and acquistion. The new edition expands the treatment of polysemy, meaning relatedness, idioms and grammatical constructions The book presupposes no prior knowledge of linguistics and will therefore be particulary suited to undergraduate courses.