Sleep is a paradox. Or at least, it kind of seems that way when examined from an evolutionary standpoint. When we’re asleep, we have diminished awareness of our surroundings, leaving us vulnerable to predators and other threats in the environment. And from a practical perspective, lying down with your eyes closed for eight hours also seems like a fairly unproductive behavior, which no doubt is why high-achieving people throughout history have sought to get by with less of it. Despite these obvious disadvantages, we spend about a third of our life in slumber. And not just us – some form of sleep is nearly ubiquitous in the animal kingdom. Finally, as everyone knows all too well, disturbances to sleep can have a serious negative impact on our physical and mental health, making it hard to minimize even if you really want to. The universality of sleep, as well as our inexorable need for it, in the face of its costs, suggests that sleep is extremely important . But for what spe