This text presents a comprehensive account of the magnetic fields of various celestial bodies - the Sun, the Moon, planets, stars, the Milky Way, and galaxies, as well as the interplanetary, interstellar and intergalactic media. The original Chinese edition was published in Beijing in 1978. The present English edition has been enhanced and thoroughly rewritten. This monograph is characterized by its detail and may be used as a reference and textbook for scientific researchers and students of astronomy, space physics, geophysics and other related sciences.