This book is a provocative contribution to contemporary ethics and moral psychology, challenging fundamental assumptions about character dating to Aristotle. John Doris draws on an array of social scientific research, especially experimental social psychology, to argue that people often grossly overestimate the behavioral impact of character and grossly underestimate the behaviorial impact of situations. Circumstance, Doris concludes, often has extraordinary influence on what people do, whatever sort of character they may appear to have. He then considers the implications of this observation for a range of issues in ethics, arguing that with more realistic picture effect, cognition, and motivation, moral psychology can support more compelling ethical theories and more humane ethical practices.