This book deals with words, and how humans learn them, remember them, understand them, and find the ones they want. In brief, it discusses the structure and content of the human word-store or 'mental lexicon', with particular reference to the spoken language of native English speakers. Since the first edition of this book was published, work on the lexicon has exploded. This is reflected in this new edition, which contains substantial additions. Two new chapters have been added, and others have been considerably expanded. No chapter remains unaltered, and over 300 new references have been added as notes and suggestions for further reading. The book remains accessible in style, easy to read for both undergraduates and non-specialists.