## TL;DR
Economics studies how societies allocate scarce resources. Supply and demand form the core analytical framework, while GDP, inflation, and unemployment are the headline macroeconomic indicators.

## Core Explanation
Microeconomics: consumer theory (utility maximization), producer theory (profit maximization), market structures (perfect competition, monopoly, oligopoly), externalities (pollution), public goods. Macroeconomics: GDP, inflation (CPI), unemployment, fiscal policy, monetary policy (interest rates).

## Detailed Analysis
Elasticity measures responsiveness: price elasticity of demand = %ΔQ/%ΔP. Perfectly inelastic demand has elasticity=0. Game theory analyzes strategic interactions (prisoner's dilemma, Nash equilibrium). Comparative advantage explains gains from trade.

## Further Reading
- OpenStax: Principles of Economics (free)
- IMF World Economic Outlook
- The Economist