This is the 11th volume in the New Directions in Cognitive Science Series (formerly Vancover Studies in Cognitive Science). It addresses common sense, reasoning, and rationality, currently areas of considerable interdisciplinary interest and importance. While common sense and rationality have often been viewed as two distinct features in a unified cognitive map, this interdisciplinary volume - including essays from an outstanding group of established scholars - engages with this notion and comes up with novel and often paradoxical views of this relationship. It should appeal to philosophers, psychologists, cognitive scientists, and computer scientists interested in considering what constitutes human rationality, behaviour, and intelligence. This groundbreaking collection is at the forefront of Cognitive Science research, and promises to be of unprecedented influence across disciplines.