Special attention is given in the monograph to the effect of the type and concentration of impurity and alloying elements and also phase changes on the mechanism of buildup of radiation defects and damage to metallic materials under irradiation. An important section of the book is concerned with the calculation and experimental evaluation of the activation parameters of individual chemical elements and alloys, and a number of methods of reducing the activation of materials is examined. General problems and directions of the development of reduced-activation radiation-resistant alloys are analysed. The final chapter deals with the main experimental relationships and mechanisms of radiation damage in a number of pure metals and constructional materials for atomic engineering