The monograph was written by one of the leading experts in the field and includes consideration of current problems of plasma physics. The book is an introduction to the theory of collective phenomena in plasma, it gives a general idea of ​ ​ both regular nonlinear phenomena (such as nonlinear weakly dispersing waves, echoes in plasma, nonlinear Landau attenuation, parametric effects, etc.), and plasma turbulence, i.e. irregular noises developing due to instabilities. The presentation of the material is carried out, if possible, in the most accessible form.