We all face decisions where the outcome is not under our control — whether to carry an umbrella, launch a new product, or accept a job offer. Decision analysis gives you a structured way to think through these choices, weigh the possible futures, and pick a path that makes sense, even when the future is cloudy. By the end of this chapter you will have a toolkit for reasoning clearly about uncertainty, using decision trees, expected value, the cost of not knowing, and a way to capture your own comfort with risk.