This book is devoted to some aspects of the theory of strong electromagnetic wave-plasma interaction. The various nonlinear mechanisms of the steady-state electrical and magnetic field generation by an electromagnetic wave in a plasma are considered. The theory of the nonreflective propagation of an electromagnetic wave through a dense plasma is developed. The results of the nonlinear theory of fast plasma waves excitation by single and double-frequency electromagnetic pulses in rare plasma are presented. The method of electron acceleration by laser radiation is discussed. Plasma synergetics including nonstationary structures are studied. The influence of plasma motion on the generation of fast particles and harmonics is investigated. It is shown that the electrical field amplitude near the critical density layer for a wave propagating towards the supersonic plasma stream is limited and it decreases with increase of plasma inhomogeneity length.