Energies: An Illustrated Guide to the Biosphere and Civilization

The energy of solar radiation reaching the earth clocks in at 5,500,000 exajoules, an exajoule being one watt per second taken to 10 to the 18th power. The energy used to strike a typewriter key is 20 millijoules, a millijoule being one watt per second taken to 10 to the negative 3rd power; that keyboard-striking energy is a full order of magnitude larger than the energy a flea expends in hopping from one spot to another. Such is the sort of information that geographer Vaclav Smil delights in presenting in his endlessly interesting handbook of the various energy technologies of nature and culture. "Energy is the only universal currency," Smil writes, but, he notes, it is little understood. Beginning with a grand tour of the solar system and the terrestrial biosphere, and taking into account such matters as the movement and latent heat of waves, Smil moves on to consider the energy of natural food chains, the efficiency of human growth, the energy requirements of agriculture, and the terrible force of modern weapons, among hundreds of other subjects. His heavily illustrated book is one of a kind, and it makes for both entertaining bedside reading and a highly useful reference. --Gregory McNamee