Our sun drives the weather, forms the landscape, feeds and fuels—but sometimes destroys—the creatures that live upon it. Scoping out the ways that earth is ruled by its nearest star, Steve Jones notes connections between the need to stay cool and man's ability to stand upright, between the power of memory and the onset of darkness, between the flow of solar energy through the plants and animals and of wealth through society. Here too is an examination of the genetic and evolutionary effects of sunlight on snails, fruit-flies, and Scots.