First published in 1985 (MIT Press), Fauconnier’s influential book, Mental Spaces, was instrumental in shaping the new field of cognitive linguistics. The concept of mental spaces–that we develop constructs during discourse that are distinct from linguistic constructs but are established by linguistic expressions–provides a powerful new approach to problems in philosophy and cognitive science concerning thought and language. It includes a new preface that provides context for the theory, and a new foreword by George Lakoff and Eve Sweetser (both of U.C. Berkeley).