In 1992, Law and Philosophy published an account of the paradigm case of intended action; one which gestured at, and did not pursue, an explanation of the requirement that a person be an agent in respect of her behaviour before that behaviour can constitute intended action. This paper completes that account by supplying an analysis of agency. The paper falls into three parts. It begins by casting doubt upon the possibility of specifying a causal account along the lines once envisaged (...) by Davidson. An alternative approach is adopted: one that involves modifications to Frankfurt's depiction of action as behaviour under the agent's guidance, including a rejection of the view held by many writers that action requires intentional movement. Doubts about conventional wisdoms are also raised in the conclusion, which considers why philosophers and lawyers should be interested in the issue of agency at all. (shrink)