This book provides analytical methods for predicting temperature distribution in isotropic and anisotropic composite media for both steady and transient states, with a focus on how temperature differences affect the properties of composite materials. In so doing, the text offers original equations for the behavior of heat conduction. To begin, steady-state heat conduction in fiber-reinforced and particulate composites is described from a micromechanics point of view. Analytical solutions are furnished for steady- state and transient heat conduction in laminated composites, with a focus on the special equations for the transient conditions. Next, a theoretical overview is given of rapid energy transport in heterogeneous composites under a local thermal non-equilibrium condition. This is followed by a discussion of the effective thermal conductivity of unbounded composites using models such as those of Hashin/Shtrikman, Maxwell-Garnett effective medium theory, Mori- Tanaka, and self-consistent approximation. The final part investigates thermal stresses caused by a mismatch of the thermal expansion coefficients at the interface of matrix and fibers due to non-uniform temperature distribution. In this way, connections with engineering implications are drawn between thermal stress analysis and the unique methods and results for investigating heat conduction presented in the initial chapters of the book.