hiany components in supersonic aircraft and modern power plant operate under cyclic conditions at increased temperatures at which creep processes also occur. Solving associated material problems depends, to a major extent, on understanding the various factors influencing behaviour, such as the effect of stress or strain cycling, dwell periods, temperature, notches, environment, multiaxial stress, ductility, and the effect of prior testing on subsequent endurance. T h e various methods of testing are briefly described and the mode of failure where there is interaction between creep and fatigue is discussed. Method5 for predicting deformation and life are also presented. Finally, the review concludes with suggestions for future work.