How do we think about the worlds we live in? The formation of categories of events and objects seems to be a fundamental orientation procedure. Facet theory and its main tool, the mapping sentence, deal with categories of behavior and experience, their interrelationship, and their unification as our worldviews. In this book Hackett reviews philosophical writing along with neuroscientific research and information form other disciplines to provide a context for facet theory and the qualitative developments in this approach. With a variety of examples, the author proposes mapping sentences as a new way of understanding and defining complex behavior.