The monograph is devoted to phenomena of nonlinear optics appearing on a macro scopic level in the interaction of intense light with an isolated atom. It is a first attempt to summarize the elementary phenomena of nonlinear optics and present the various methods used in experiment and theory. In essence, this book can be considered an expanded version of the new aspect of quantum mechanics and atomic physics that in time will be incorporated into te- books on this subject. By the middle of this century the interaction of light with atoms had become one of the most investigated branches of...