Energy is the only universal currency. One of its many forms must be transformed into another in order for stars to shine, planets to rotate, living things to grow, and civilizations to evolve. Recognition of this universality was one of the great achievements of nineteenth-century science, yet even today there is little literature that tries to view the world broadly through the prism of energy.In this highly original book, ecologist Vaclav Smil takes the principle of universality seriously, presenting a comprehensive and integrated survey of all the forms of energy that shape our world, from the sun to the human body, from bread to microchips. Written in a scientifically sophisticated yet accessible style, Energies consists of eighty-two short essays organized under six headings: Sun and Earth, Plants and Animals, People and Food, Preindustrial Societies, Fossil-Fueled Civilization, and Motion and Information. Each essay explains the science of the energy form as well as its implications for the functioning of the universe, life, or human society. Cross-links and summary diagrams allow easy comparisons among the various levels and flows of energy.