"Sleepers cannot live for long with an insomniac. It is like living with something supernatural: people who are normal come to feel it as a shadow on their own lives. And they come to feel it quite soon. The man or woman who in the true sense cannot sleep is a kind of troll, as they call it here. Life is so made that without sleep only a troll can endure it. The sleepers have no alternative to driving us out."

Robert Aickman, "Into The Wood"