An expert account of the immense international research effort to develop practical nuclear fusion. Physicist and science writer Turrell reminds readers that burning fossil fuels provides 86% of the world’s energy. Scientists warn that we must massively reduce this number in order to avoid climate catastrophe, but it’s still growing. The author and the researchers he has consulted have a low opinion of renewables such as solar, wind, and hydropower. They feel that atomic power is a good method despite its problems, including public relations problems and issues related to scale. One possible solution is controlled nuclear fusion. Fusion produces 10 million times the energy of coal. Turrell explains that the process of two hydrogen atoms slamming together to form a helium atom releases immense energy but also requires titanic pressure and heat. Scientists can achieve fusion in the lab, but this requires expending energy. It happens deep within the sun, so current research projects require confining hydrogen under immense pressure and at millions of degrees of temperature. Since no container could survive contact with such material, this must take place in midair. Traveling the world, Turrell describes wildly complex efforts to achieve this with combinations of magnetism, inertia, pressure, and lasers. These efforts sometimes work, but only for short periods. No project has yet produced more energy than it consumes, but scientists are optimistic. One famous quip notes, “Fusion is the energy of the future…and always will be.” A diligent journalist, Turrell does not overhype his subject, delivering a painless education with asides on the history of the universe, the life cycle of stars, and the dismal consequences if we don’t stop burning fossil fuels. According to the author and countless scientists, this can only happen if nuclear fusion succeeds. “The ingredients of even the most basic form of fusion…could last us around 33 million years,” he writes. Important, high-quality popular science.