Imagine you’re choosing between two routes to school. Route A always takes 20 minutes. Route B takes 15 minutes if there’s no traffic, but 40 minutes if there is. You don’t know the traffic, but no matter what, A is never worse—and sometimes strictly better. That’s the heart of dominance: a choice that outperforms another in every possible situation. In this chapter we’ll see how such simple comparisons can cut through the complexity of strategic games, letting us predict what rational players will do—and what they won’t do—without ever needing to guess their opponents’ exact moves.