In the highly influential mental-spaces framework developed by Gilles Fauconnier in the mid-1980s, the mind creates multiple cognitive \"spaces\" to mediate its understanding of relations and activities in the world, and to engage in creative thought. These twelve original papers extend the mental-spaces framework and demonstrate its utility in solving deep problems in linguistics and discourse theory. Investigating the ties between mental constructs, they analyze a wide range of phenomena, including analogical counterfactuals; the metaphor system for conceptualizing the self; abstract change expressions in Japanese; mood in Spanish; deictic expressions; copular sentences in Japanese; conditional constructions; and reference in American Sign Language. The ground-breaking research presented in this volume will be of interest to linguists and cognitive scientists. The contributors are Claudia Brugman, Gilles Fauconnier, George Lakoff, Yo Matsumoto, Errapel Mejias-Bikandi, Laura A. Michaelis, Gisela Redeker, Jo Rubba, Shigeru Sakahara, Jose Sanders, Eve Sweetser, and Karen van Hoek.