Later this month, the U.S. Department of Energy will receive a report from a panel of experts on the prospects for cold fusion—the supposed generation of thermonuclear energy using tabletop apparatus. It's an extraordinary reversal of fortune: more than a few heads turned earlier this year when James Decker, the deputy director of the DOE's Office of Science, announced that he was initiating the review of cold fusion science. Back in November 1989, it had been the department's own investigation that determined the evidence behind cold fusion was unconvincing. Clearly, something important has changed to grab the department's attention now. The cold fusion story began at a now infamous press conference in March 1989. Stanley Pons and Martin Fleischmann, both electrochemists working at the University of Utah in Salt Lake City, announced that they had created fusion using a battery connected to palladium electrodes immersed in a bath of water in which the hydrogen was replaced with its isotope deuterium—so-called heavy water. With this claim came the idea that tabletop fusion could produce more or less unlimited, low-cost, clean energy. In physicists' traditional view of fusion, forcing two deuterium nuclei close enough together to allow them to fuse usually requires temperatures of tens of millions of degrees Celsius. The claim that it could be done at room temperature with a couple of electrodes connected to a battery stretched credulity