The monograph adopts the Monte Carlo approach to treat macroscopic radiative heat transfer phenomena. It is to divide a phenomenon into a number of basic processes. The sum of the individual processes simulate the behavior of the entire physical phenomenon. Hence, the probability distribution for the occurrence of each basic process as well as the physical laws that govern the processes must be obeyed. The conventional flux and zone methods cannot treat the problems of specular reflection or gas scattering in the analysis of radiative heat transfer. In contrast, the Monte Carlo method has flexibility in dealing with various governing parameters and operating conditions, such as three-dimensionality and arbitrary wall boundary conditions (for example diffuse reflection, specular reflection, anisotropic scattering, a non-gray body with wave length-dependent physical properties, etc.). It is relatively simple to develop computer programs for radiative heat transfer analysis by means of the Monte Carlo method.