The document discusses how banks create money through fractional reserve banking. It begins by explaining how goldsmiths in the early days would lend out receipts for gold they held, even though they did not hold all the gold in reserve. This created the fractional reserve system. It then provides examples of how a commercial bank's balance sheet changes as it accepts deposits, makes loans from excess reserves, and purchases assets like government securities. The document also discusses the monetary multiplier effect, where one bank's loans become another bank's deposits, expanding the money supply. It concludes by noting that monetary policy will be covered in the next chapter.