This book deals with the problem of a bearing capacity and fracture of thermally loaded materials. The treatise is based on extensive experimental and technological data of materials-development processes for high-temperature nuclear reactors and aerospace nuclear-rocket engines. New regularities and irregularities of fracture at various modes of local and combined thermal loading using electron-beam, induction and ionic-beam technique of heating, and also with traditional methods of measuring the thermal stress resistance are discussed. New criteria for the estimation of the bearing capacity of bodies in inhomogeneous fields of thermal and residual stresses are developed on the basis of fracture mechanics. Changes in the thermal stress resistance of carbides (ZrC, NbC, and SiC), graphite, Si3N4, Y2O3, Sc2O3 Al2O3 and single crystals of sapphire are considered. Possible technological methods for the improvement of thermal stress resistance are also presented.