Revision with unchanged content. While most philosophers agree that intentional actions play an important role in our ascriptions of responsibility, there is disagreement concerning the precise nature of this role. Unfortunately, there has traditionally been a dearth of empirical data about ascriptions of intentional action. Lately, however, researchers have begun filing in this empirical lacuna. In this book, I discuss how this research sheds light on problems in action theory, ethics, and legal philosophy. In doing so, I first set the stage by discussing some of the problems traditionally associated with the concept of intentional action before turning my attention to recent research on the folk concept of intentional action. Finally, I compare and contrast the folk concepts of intention and intentional action with their legal counterparts. My goal is to flesh out the extent to which these concepts diverge-a problem that is particularly pressing given that in litigated cases involving juries, jurors are often asked to judge whether the defendant acted intentionally, purposely, and knowingly. This book is addressed to philosophers and psychologists working at the intersection of folk psychology and the law.