This volume about words, and the extraordinary human capacity to store and retrieve them. We hold effortlessly at least 50,000 of them in our minds, the majority of which can be summoned in a split second. No computer has yet come anywhere near simulating the complexities of the internal word-store. This book provides an up-to-date introduction to man's prodigious "mental lexicon". Using evidence from "slips of the tongue", the word-finding problems of aphasics, psycholinguistic experiments and the research of theoretical linguists, it describes: how man deals with this fluctuating mass of words; how people use fluid prototypes rather than fixed definitions for coping with meaning; how we extend old words and create new ones. The book compares the verbal resources of adults and children, and assesses recent competing theories as to how we seek out the lexical items we need. It is designed both for students embarking on psycholinguistics courses, and for anyone who has ever puzzled about the human word-store.