Money is a system of tokens that represent purchasing power. It evolved from debt, barter, and coins to gold-backed currencies, bank credit, and now digital currencies. Over the past 50 years, wages have stayed the same, household borrowing has increased, and the economy has become more complex. The banking and financial system plays a crucial role in coordinating economies as complex systems. Understanding money is important for economics and finance students and anyone interested in monetary theory, economics, and banking.