Some physiologists claim that the brain accesses the most energy in the human body. Others say it is the heart, witness the politicians or grant reviewers who must assuredly be “brain dead,” while remaining perfused... This year has marked the arrival of the 6 billionth person on the planet. Six billion hearts that must beat ceaselessly day and night—and the smallest discrepancy warrants a visit to your local cardiologist, provided you can afford it. How does the world support this tremendous energy expenditure? Biological energetics cannot use fossil fuels, so where is the energy feedstock to drive the mushrooming human population?...