This chapter provides brief overview of the Aristotelian view of the nature and role of practical wisdom in the life of a virtuous person. It focuses on the practical wisdom that is necessary for virtue and the "unity of virtue" thesis, and follows from the first: if practical wisdom is required for each individual virtue, then a person who has one virtue will also have the others. According to Aristotle, practical wisdom is an intellectual virtue that makes it possible for a virtuous person to act well. Aristotelians give three closely related reasons in favor of the claim that practical wisdom is required for virtue. Aristotle defends a strong version of the unity of virtue thesis, namely that if a good person has practical wisdom, then she will possess all the virtues. Driver thinks modesty serves as a counter-example to the Aristotelian claim that virtue requires knowledge.