To what extent can animal behavior be described as rational? What does it even mean to describe behavior as rational? This book focuses on one of the major debates in science today: how closely does mental processing in animals resemble mental processing in humans? It addresses the question of whether and to what extent non-human animals are rational, that is, whether any animal behavior can be regarded as the result of a rational thought process. With a distinguished line-up of leading thinkers from philosophy and psychology, the book presents the first multidisciplinary examination of this topic.