A concise, practical guide that traces thermal management from the microchip to the data center. It explains how heat is generated at the transistor level, and how cooling strategies, conduction, convection, liquid immersion, and phase change cooling, scale up to keep entire data centers reliable and energy-efficient. The book blends fundamentals (heat transfer, modeling, materials) with real-world design guidelines, case studies, and best practices for engineers, researchers, and students working on electronics cooling across all scales.