Hans Bethe, the German American physicist, was one of the world's leading scientific authority on energy. He spent a lifetime on energy-related questions and was a source of information about alternative sources of energy. This work provides a discussion of what the real options are in the energy field are. How much energy will we need, what it will cost, and what are its available sources? How does the process of energy conversion, whether nuclear, solar, or conventional oil and coal, actually work?