By focusing on the idea that agency involves causal sensitivity to reasons, Rowland Stout shows how agency is one of the most useful ways into the philosophy of mind: if one can understand what it is to be a free and rational agent, then one can understand what it is to be a conscious subject of experience. Some of the questions considered include: Is all action intentional action? Is intentional action characterized by its relation with possible justification? Do beliefs motivate actions or do facts? What is the nature of the causal process of acting? Are intentions independent components in the explanation of action? The traditional Davidsonian agenda remains central but Stout locates it historically in relation to the ideas of Aristotle and Kant as well as current issues of interest such as externalism, moving the debate beyond Davidson. This fresh and engaging introduction to the many philosophical problems associated with agency is ideally suited for the study of the philosophy of action, philosophy of mind, and metaphysics.