The theme of the book is the conquest of absolute zero temperature. The historical aspect of the problem helps the author to express the dramatic nature of the development of science, the "drama of ideas," and to acquaint the unprepared reader with the complex equipment used to obtain ultra-low temperatures. Much attention is paid in the book to Soviet low-temperature installations, including installations created by academician P.L. Kapitsa. In a popular form, the author introduces the reader to the thermodynamic principles of obtaining low temperatures. The most detailed chapters of the book are devoted to the discovery of the phenomenon of superconductivity and the creation of superconducting magnets in recent years, as well as the discovery and subsequent explanation by Soviet physicists of the phenomenon of superfluidity.