Practical wisdom (hereafter simply "wisdom") is the intellectual virtue that enables a person to make reliably good decisions about how, all-things-considered, to live and conduct herself. Because wisdom is such an important and high-level achievement, we should wonder: what is the nature of wisdom? What kinds of skills, habits and capacities does it involve? Can real people actually develop it? If so, how? I argue that we can answer these questions by modeling wisdom on expert decision-making skill in complex areas like firefighting. I develop this expert skill model of wisdom using philosophical argument informed by relevant empirical research. I begin in Chapter 1 by examining the historical roots of analogies between wisdom and practical skills in order to motivate the expert skill model. In Chapter 2, I provide the core argument for the expert skill model. I then use the remaining chapters to pull out the implications of the expert skill model. In Chapter 3, I show that the expert skill model yields practical guidance about how to develop wisdom. In Chapter 4, I address the objection, due to Daniel Jacobson, that wisdom is not a skill that humans could actually develop, since skill development requires a kind of feedback in practice that is not available for all-things-considered decisions about how to live. Finally, in Chapter 5, I apply the expert skill model to the question, much discussed by virtue ethicists, of whether a wise person deliberates using a comprehensive and systematic conception of the good life.