The document discusses the business cycle, which consists of four phases: expansion/growth, peak, recession, and trough/depression. During expansion, spending and employment rise until reaching a peak. Then a recession begins as spending and employment fall. The cycle bottoms out at a trough, with low production and high unemployment, before beginning expansion again. The business cycle is influenced by internal factors like consumption, investment, and government policy, as well as external factors such as technology and wars. The government uses fiscal and monetary policy to stabilize the economy and prevent severe recessions or inflation.