The opening scene of Marcel Proust’s Swann’s Way is one of the most famously difficult to get through in literature. That’s not because of its style, which is sublime, but because it describes the experience of falling asleep. Many susceptible readers nod off the first few times they attempt it. All writing about sleep has this problem; of the fundamental human appetites, it’s the least exciting. The better you invoke it, the more likely you are to incite it, and because it can’t be remembered, sleep can’t be described.