Aristotle's Ethics develops a complex theory of the qualities which make for a good human being and for several decades there has been intense discussion about whether Aristotle's theory of voluntariness, outlined in the Ethics, actually delineates what modern thinkers would recognize as a theory of moral responsibility. Javier Echeñique presents a novel account of Aristotle's discussion of voluntariness in the Ethics, arguing - against the interpretation by Arthur Adkins and that inspired by Peter Strawson - that he developed an original and compelling theory of moral responsibility and that this theory has contributed in important ways to our understanding of coercion, ignorance and violence. His study will be valuable for a wide range of readers interested in Aristotle and in ancient ethics more broadly.