INTRODUCTION Energy is what makes things move, light up, and radiate warmth—energy makes things happen and makes our lives easier, too. We use huge amounts of energy to transport people and things, to produce goods, to heat and light our homes, to communicate with each other, and to travel into space. Energy is one of the basic necessities of our universe. This is particularly true in the United States: Americans make up only four percent of the world's population, but use 24 percent of the world's energy. Science cannot resolve moral conflicts, but it can help to more accurately frame the debates about those conflicts. —Heinz R. Pagels, The Dreams of Reason