This document discusses the late 2000s recession and its origins. It notes that recessions are normal fluctuations in the business cycle where macroeconomic quantities like output and unemployment move together. The recession had many interrelated causes, including the housing bubble and subsequent crash, loose lending standards and securitization of risky mortgages, underestimation of risk in financial markets, and excessive leverage and complexity in the financial system. This convergence of factors led to a stock market crash, financial crisis, and broader economic downturn on a global scale from 2007-2008.