The story of energy is simple. Once upon a time all work was done by people for themselves using their own muscles. Then there came a time when some people got other people to do the work for them, and the result was pyramids and leisure for a few, drudgery and exhaustion for the many. Then there was a gradual progression from one source of energy to another: human to animal to water to wind to fossil fuel. In each case, the amount of work one man could do for another was amplified by the animal or the machine.
