Lucy O'Brien argues that a satisfactory account of first-person reference and self-knowledge needs to concentrate on our nature as agents. She considers two main questions. First, what account of first-person reference can we give that respects the guaranteed nature of such reference? Second, what account can we give of our knowledge of our mental and physical actions? Clearly written, with rigorous discussion of rival views, this book will be of interest to anyoneworking in the philosophy of mind and action.