How can we identify the causes of events? What does it mean to assert that someone is responsible for a moral affront? Under what circumstances should we blame others for wrongdoing? The related, but conceptually distinct, issues of causality, responsibility, and blameworthiness that are the subject of this book play a critical role in our everyday social encounters. As very young children we learn to assert that it wasn't my fault, or that I didn't mean to do it. Responsibility and blame follow us into adulthood, as personal or organizational failings require explanation. Although judgments of moral accountability are quickly made and adamantly defended, the process leading to those judgments is not as simple as it might seem. Psychological research on causality and responsibility has not taken complete advantage of a long tradition of philosophical analysis of these concepts. Philosophical discussions, for their part, have not been sufficiently I1ware of the psychological realities. An assignment of blame is a social explanation. It is the outcome of a process that begins with an event having negative consequences, involves judgments about causality, personal responsibility, and possible mitigation. The result can be an assertion, or a denial, of individual blameworthiness. The purpose of this book is to develop a comprehensive theory of how people assign blame.