A concise and fascinating -- if occasionally technical -- account of the sources and uses of energy of all kinds. Smil starts by describing the earth as an energy system, receiving energy from the sun, internally generating some as well, and radiating it back into space. He then discusses the relationship between energy and the biosphere and devotes a chapter to the body of that very special creature, homo sapiens. An account of the social uses of energy, from fire in primitive society to rocket engines, concludes the book. Smil covers topics ranging from primitive hunting techniques (like how some humans could run down faster prey) to Chinese natural-gas wells in 200 B.C. (another Chinese first). Filled with interesting factual tidbits, useful charts and drawings, and relevant background on policy issues such as global warming and increased energy security, this book rekindles the fascination with science that we all once had as children.