The brochure is devoted to one of the main problems of rocket navigation - spacecraft engines. It quite fully describes the design of rocket engines of the present and future and the principles of their operation. At the same time, the author pays special attention to clarifying the physics of phenomena in engines. The popularity of the brochure is combined with a high scientific level of presentation. The advantage of the brochure is also in a clear distinction between today's projects and projects of the distant future, science fiction proposals.