The inscription on the Oracle of Delphi reads "Nothing in excess." C.S. Lewis described temperance as going to the "right length but no further." Easy to say, hard to practice — if it was tough in 300 BC or in the 1940s, it feels almost impossible today. Yet it is one of the most empowering and important virtues we can learn. Without self-discipline, all our plans fall apart. Here, Ryan Holiday shows how to cultivate willpower, moderation, and self-control. From Aristotle and Marcus Aurelius to Toni Morrison and Queen Elizabeth II, he illuminates the great exemplars of these practices and what we can learn from them. Moderation is not about less; it is about self-respect, focus, and balance. Without it, even the most positive traits become vices. With moderation, happiness and success follow — the key is not more, but finding the right amount.