The energy that we receive from the Sun is born in its bowels, where thermonuclear fusion reactions take place - hydrogen turns into helium. If it were possible to use these reactions on Earth, humanity would provide itself with energy in abundance. For thirty years now, the thermonuclear problem has remained the central problem of physics, and only now it has become clear that it is still possible to solve it. In a lively and accessible form, the book tells about how these areas developed, about the outstanding contribution of Soviet scientists to solving the thermonuclear problem, about witty ideas, bold experiments, successes and failures in the fight against insidious and elusive plasma. For schoolchildren, teachers, students, lecturers.