This book introduces fusion energy as a promising solution for curbing global warming and explains why accelerating its practical use is essential. Designed for beginners—especially undergraduate students—it bridges the gap between introductory and specialized texts. Unlike many existing books that are either too general or heavily mathematical, this book uses clear diagrams and simple arithmetic to explain plasma physics, reactor engineering, and safety. It highlights the ingenuity behind fusion plant components and compares fusion with other energy sources through energy conversion efficiency. By presenting key developments in plasma physics and reactor design in an accessible way, this book aims to spark interest in fusion and nurture the next generation of researchers.

Dr. Takashi Okazaki has conducted fusion research, including plasma heating and current drive, blanket, divertor, and safety, and has also been involved in the conceptual design of fusion reactors. In particular, in the field of plasma heating and current drive, he proposed a current drive method with high current drive efficiency. He also introduced the concept of a steady-state operation tokamak reactor, which made a significant contribution to the steady-state operation of tokamak. With the aim of realizing the experimental reactor, International Tokamak Reactor (INTOR, 1978–1987) was promoted under the initiative of the IAEA, and now International Thermonuclear Experimental Reactor (ITER, 1988–) is being promoted as a subsequent project. He was a member of INTOR Phase Two A Part III.