Withtheappearanceoflasershavecomerealpossibilitiesofrevealingnum- ous nonlinear phenomena of diverse nature resulting from the interaction of strong electromagnetic ?eld either with matter or with free charged particles. First attempts of investigators, especially experimentalists, were directed - ward studying the processes of interaction of laser radiation with matter, which led to the rapid formation of a new ?eld -- Nonlinear Optics. The numerous published monographs on this subject are evidence of that. The situation regarding the processes of interaction of laser radiation with free...