Imagine you are at the controls of a giant ship—the economy. Your job is to keep it moving at just the right speed: fast enough that people who want jobs can find them, but not so fast that prices spiral out of control. The levers you pull are surprisingly simple, but their effects ripple through millions of daily decisions. In this chapter, we’ll look at those levers—the tools of monetary policy—and trace how a small change in a short‑term interest rate can steer the whole economy.