To see what a hard question this is, let’s conduct a fanciful, but hopefully illuminating, thought experiment. Throw your mind back into the mists of prehistory. Imagine that there are just two human tribes living side by side in some African valley. They are competing for the same finite resources: one tribe will gradually die off, and the other will inherit the earth. One tribe is called the Practical People and one is called the Story People. The tribes are equal in every way, except in the way indicated by their names.Most of the Story People’s activities make obvious biological sense. They work. They hunt. They gather. They seek out mates, then jealously guard them. They foster their young. They make alliances and work their way up dominance hierarchies. Like most hunter-gatherers they have a surprising amount of leisure time, which they fill with rest, gossip, and stories—stories that whisk them away and fill them with delight.Like the Story People, the Practical People work to fill their bellies, win mates, and raise children. But when the Story People go back to the village to concoct crazy lies about fake people and fake events, the Practical People just keep on working. They hunt more. They gather more. They woo more. And when they just can’t work anymore, the Practical People don’t waste their time on stories: they lie down and rest, restoring their energies for useful activity.Of course, we know how this story ends. The Story People prevailed. The Story People are us.If those strictly practical people ever existed, they don’t anymore. But if we hadn’t known this from the start, wouldn’t most of us have bet otherwise? Wouldn’t we have bet on the Practical People outlasting those frivolous Story People?The fact that they didn’t is the riddle of fiction. Evolution is ruthlessly utilitarian. How has the time-gobbling luxury of fiction not been eliminated from the human repertoire?In short, no one knows for sure.But researchers are converging on a possible solution. Drawing on research in dreams, pretend play, and world fiction, I explore the possibility that stories are the flight simulators of human life. Fiction projects us into intense simulations of problems that parallel what we face in reality. And, like that of a flight simulator, the main virtue of fiction is that we have a rich experience and don’t die at the end. We get to simulate what it would be like to confront a dangerous man or seduce someone’s spouse, for instance, and the hero of the story dies in our stead.This book uses insights from biology, psychology, and neuroscience to try to understand the storytelling instinct. I am aware that the very idea of bringing science—with its sleek machines, its cold statistics, its unlovely jargon—into Storyland makes many people nervous. Fictions, fantasies, dreams—these are, to the humanistic imagination, a kind of sacred preserve. They are the last bastion of magic. They are the one place where science cannot—should not—penetrate, reducing ancient mysteries to electro-chemical storms in the brain or the timeless warfare among selfish genes. The fear is that if you explain the power of Neverland, you may end up explaining it away. As Wordsworth said, you have to murder in order to dissect.But I disagree. Science adds to wonder, it doesn’t dissolve it. Scientists always report that the more they discover, the more lovely and mysterious things become. As the great novelist and distinguished lepidopterist Vladimir Nabokov once put it, “The greater one’s science, the deeper the sense of mystery.” That’s certainly what I found in my own research. The whole experience left me in awe of Homo fictus—the beast who lives in fiction.