Aristotle and Augustine both hold that our beliefs in freedom and voluntary action are interdependent, and that voluntary actions can only be done for the sake of good. Hence Aristotle holds that no-one acts voluntarily in pursuit of evil; such actions would be inexplicable. Augustine, agreeing that such actions are inexplicable, still insists that they occur. This is the true place in Augustine's view of his "theory of will", and the real point of contrast between Aristotle and Augustine. In this text, the author takes up the suggestion made by J.L. Austin that the way to understand "free will", and Aristotle's discussion of freedom, is by seeking an understanding of what voluntary action is. This book makes the claim: that there are three conditions for voluntary action (namely, freedom from compulsion, from ignorance, and from irrationality) not two, as is usually held (namely, freedom from compulsion and from ignorance). The book also examines Aristotle's discussion of akrasia and reconsiders the contrast between Augustine and Aristotle, as well as focusing on Augustine as a philosopher of action.