Energy is crucial for events of every kind, in this world or any other. Without energy, nothing would ever happen. Nothing would move and there would be no life. The sun wouldn't shine, winds wouldn't blow, rivers wouldn't flow, trees wouldn't grow, birds wouldn't fly, and fish wouldn't swim; indeed no material object, living or dead, could even exist. In spite of all this, energy is seldom considered a part of what we call "nature." In The...