This Edition translated from V. L. Ginzburg’s book entitled“ PacnpocTpaiieiiiie ojieKTpoMamiiTHLix bojih b miasMe’1 (Rasprostraneniye elektromagnitnykh voln v plazme) published by Fizmatgiz, Moscow, 1960 The present book deals with such problems, which are of importance in the theory of radio wave propagation in the Earth’s ionosphere, in radio astro­nomy and astrophysics, and in the physics of laboratory plasmas.