Controlled fusion, mini-stars, energy from sea water: the slogans and promises of energy from thermonuclear reactions of the kind that occur at the heart of stars and in hydrogen bombs have made headlines over the decade. Science writer Heppenheimer (Colonies in Space, Toward Distant Stars) brings it all together in a savvy state-of-the-art summary. No, controlled fusion is not here yet; but Heppenheimer lays out proposed schedules and presents an indefatigable cast working 'round the clock to make it come to pass. Part of their energy comes from competition: the race is on between Princeton, with its doughnut-shaped magnetic bottle configuration for housing the high-temperature ionized gas (plasma) that serves as the energy source, and Lawrence Livermore National Laboratory, with a cylindrical configuration making use of mirror refection principles. Still a third, privately-developed contender is a Iaser fusion model (where pellets of gas are zapped under pressure by high-energy laser beams). The impetus to develop fusion energy has waxed and waned. When outspoken Robert Hirsch rose to power in Federal energy agencies, the universities knew they had a friend in court--but also one who looked sharply at what the labs were doing, demanding goals and set deadlines. All this is presented in engaging on-the-scene reportage with personality sketches and enough technical lore to woo the average reader of Popular Science or Scientific American. Not only does fusion technology demand expertise in plasma physics, electromagnetism, and lasers, but also materials design and engineering. Coming up with the materials and specifications for equipment that must withstand stellar temperatures, and generating power to provide the energy to ignite the nuclear reactions, are themselves formidable tasks. (Right now more power is used up trying to generate a fusion reaction than comes out at the other end.) So there's enough here for the old-fashioned nuts-and-bolts buff, as well as for the astrophysically inclined--with political messages running through.