Practical wisdom is analysed here as a species of skill, using contemporary work on know-how and expert performance. Tsai argues that wisdom has two levels: a first-order practical skill at living well, and a second-order ability to say why the first-order performances succeed. He then fills in the content by importing a success theory of well-being, so the wise person knows that overall attitude success is what makes a life go well, knows the best means to it, is reliably good at reaching it, and understands why. Two objections receive extended replies. One holds that a skill cannot deliberate about its own final end; Tsai answers that experts in ordinary crafts do exactly that. The other holds that living well supplies none of the feedback skill acquisition requires; he argues that rationally defensible standards of correctness supply it. The theory is stated in four progressively refined versions, printed side by side in an appendix.