This document introduces the ten principles of economics according to Gregory Mankiw's economics textbook. It explains that economics studies how societies manage scarce resources and that individuals and societies face tradeoffs in making decisions. It discusses how rational people consider costs and benefits at the margin when deciding how to allocate resources. Markets are generally efficient but governments sometimes need to intervene to correct market failures or inequities. A nation's standard of living depends on its productivity, and inflation is often caused by increases in the money supply.