Book excerpt: From the 100-part Penguin Great Ideas series comes an excerpt from the famous Book of the Courtier. In his witty and perceptive discourses on the ideal virtues of a Renaissance courtier, Baldesar Castiglione sets out values that continue to offer illumination in questions of leadership and government—espousing such qualities as prudence, courage, loyalty, affability, and style, and even encouraging the playing of sport as one of the best ways to gain influence and power. Penguin Great Ideas: Throughout history, some books have changed the world. They have transformed the way we see ourselves—and each other. They have inspired debate, dissent, war, and revolution. They have enlightened, outraged, provoked, and comforted. They have enriched lives—and destroyed them. Now Penguin Great Ideas brings you the works of the great thinkers, pioneers, radicals, and visionaries whose ideas shook civilization and helped make us who we are. Other titles in the series include Niccolò Machiavelli's The Prince, Thomas Paine's Common Sense, and Charles Darwin's On Natural Selection.