## TL;DR
Thermodynamics governs energy transformation — from steam engines to living cells. Its four laws are universal, applying equally to black holes and biochemical reactions, making it the most broadly applicable framework in physics.

## Core Explanation
- **Zeroth Law**: Thermal equilibrium is transitive (basis of temperature measurement)
- **First Law**: Energy is conserved (ΔU = Q − W)
- **Second Law**: Entropy always increases in isolated systems
- **Third Law**: Absolute zero is unattainable

## Detailed Analysis
The Gibbs free energy (G = H − TS) determines whether reactions occur spontaneously at constant temperature and pressure — fundamental to chemistry and biology. Statistical mechanics (Boltzmann, Gibbs) bridges microscopic particle behavior with macroscopic thermodynamic properties.

Applications span: internal combustion engines (Otto cycle), refrigeration (Carnot cycle reversed), power plants (Rankine cycle), and biological metabolism (ATP hydrolysis).

## Further Reading
- HyperPhysics: Thermodynamics
- MIT OpenCourseWare: Thermodynamics & Kinetics
- Khan Academy: Laws of Thermodynamics