We tell children why it’s important to eat their vegetables. We tell them why they need to get outside and run around. But how often do we parents tell children why it’s important to sleep? “Time for bed!” is usually the end of it, or maybe “You’ll be tired tomorrow.” No wonder children regard sleep as vaguely punitive, an enforced period of dull isolation in a darkened room. But of course sleep is so much more, and maybe we ought to try telling children that.