Global warming, Arctic oil drilling, and the vanishing ozone layer are all enormous environmental problems with no clear solutions - or so conventional wisdom goes. But in the tiny town of Appalachian, Ohio, a small group of engineers under the guidance of a visionary eccentric named William Beale is challenging that conventional wisdom in an audacious attempt to transform the way the world makes and uses energy. Their "ultimate machine" - a solar-powered Stirling engine - resembles nothing the world has ever seen, and it carries an enormous burden of hope for the future of the planet. Should they succeed, a patch of desert 170 miles square could generate all the energy needs of the United States virtually pollution-free. Mark Shelton's exciting narrative takes us inside the laboratories and engine shops of Sunpower, Inc., where Beale and his colleagues are harnessing space-age technology to an idea as old as the steam engine. A working prototype of the Stirling engine is already capable of running an individual house, but enormous obstacles remain: lack of funding, and the preference of the American public and private sectors for getting their energy the good old-fashioned way. Like Tracy Kidder's Soul of a New Machine, Shelton's insightful account has the inherent drama of a report from the frontier, a frontier that might well produce the next great technological advance for the human race.