Heat transfer refers to a branch of thermal engineering which deals with the conversion, generation, exchange and utilization of thermal energy within physical systems. There are several mechanisms of heat transfer including thermal radiation, heat conduction and heat convection. There are various examples of heat transfer, such as greenhouse effect, refrigeration and maintenance of optimum temperature within the human body. Heat-transfer principles can be employed for maintaining, decreasing or increasing temperature in a variety of situations. It has numerous applications in industries such as milk pasteurization, temperature control for purified water, laser cooling, night vision cameras, and magnetic cooling. Many disciplines utilize heat transfer methods including materials processing, automotive engineering, power station engineering, insulation, chemical engineering and climate control. This book outlines the processes and applications of heat transfer in detail. It will provide comprehensive knowledge to the readers.