The proposed book was written by a classic of Russian science, one of the leaders of the Soviet atomic program, academician Ya. B. Zeldovich in the last period of his work, together with two - then young - co-authors A. A. Ruzmaykin and D. D. Sokolov (now prof. A.A. Ruzmaykin works in California, USA, and prof. D. D. Sokolov - at Moscow State University, Russia). The book was first published in English by the New York publishing house Gordon and Breach in 1983. The authors introduce here a number of new concepts of electrodynamics and magnetic hydrodynamics of space environments, in particular, they give an idea of ​ ​ a fast dynamo and a topological interpretation of the conditions for the rapid generation of a magnetic field, consider the formation of magnetic fields in spiral galaxies and in convective shells stars.