One hundred years ago, scientists and engineers were actively working on alternative energy, not because they wanted to stop burning fossil fuels but because they believed that the world would soon run out of them. This classic 1931 book reviews the sources of alternative energy that had been proposed at that time, including the famous Panropa project, whose scope would have dwarfed the Hoover Dam, along with wind power, tidal power, and others. Today most people are unaware of how much wo...