ABSTRACT
Energy is the only universal currency: one of its many forms must be transformed to another in order for stars to shine, planets to rotate, plants to grow, and civilizations to evolve. Recognitions of this universality was one of the great achievements of nineteenth-century science, but, surprisingly, this recognition has not led to comprehensive, systematic studies that view our world through the prism of energy (Vaclav Smil, Energies: An Illustrated Guide to the Biosphere and Civilization (1999), p. x).
