According to his nephew, Pliny the Elder liked to rise in the middle of the night and study by lamplight. “Admittedly, he fell asleep very easily,” Pliny the Younger wrote, “and would often doze and wake up again during his work.”

Psychologists at the University of California recognized a lack of sleep “as a social repellent” and its effect contagious: “People who come in contact with a sleep-deprived individual, even through a brief one-minute interaction, feel lonelier themselves as a result.”

“When the white man landed on the moon, my father cried,” a young Oklahoma Indian told psychologist Robert Coles in the 1970s. “He was sure Indians were crying up there, and trying to hide, and hoping that soon they’d go back to their earth, the white men.” The boy also spoke to his aunt. “The moon is yours to look at and talk to,” she told him, “so don’t worry.”

Setting grim tales during nighttime was critiqued as a cliché in 1594 by Thomas Nashe. “When any poet would describe a horrible tragical accident,” he wrote, “to add the more probability and credence unto it, he dismally begins to tell how it was dark night when it was done.”

“The difference between us is very marked,” wrote Frederick Douglass to Harriet Tubman in 1868. “Most that I have done and suffered in the service of our cause has been in public, and I have received much encouragement at every step of the way. You, on the other hand, have labored in a private way. I have wrought in the day—you in the night.”

Asked whether it was night or day that first emerged when the universe came into existence, sixth-century-bc Greek philosopher Thales of Miletus replied, “Night, earlier by a day.”

Poet Edward Fairfax kept a 1621 account of his daughter Helen’s terrible nightmares, describing an incident in which she complained about a demonic white cat that “has been long upon me and drawn my breath.” The cat, she said, “has left in my mouth and throat so filthy a smell that it does poison me.”

In September 1776, fearing illness from night air, John Adams asked Benjamin Franklin to close the window of their room in a New Jersey inn. “I believe you are not acquainted with my Theory of Colds,” Franklin responded, launching into “a harangue upon air and cold and respiration and perspiration” in favor of leaving windows open. “I was so much amused,” Adams wrote in his journal, “that I soon fell asleep and left him and his philosophy together.”

Into the early modern period, the word bug referred to a phantom in the dark; a 1535 translation of the Bible made for Henry VIII came to be known as the Bug Bible for its rendering of Psalm 91:5 as “Thou shalt not nede to be afrayed of eny bugges by night.” The word was changed to terrors in later editions, but the original sense still colors the common bedtime warning against letting bedbugs bite.

In Japanese tradition, ghosts and spirits are more likely to appear at dusk or dawn than in the middle of the night. “In order for people to see them and be frightened by them,” wrote folklorist Kunio Yanagita, “emerging in the pitch-dark after even the plants have fallen asleep is, to say the least, just not good business practice.”

A study of sixty-two mammalian species found that animals around the world have shifted into more nocturnal lives. “Humans are now this ubiquitous, terrifying force on the planet,” said lead author Kaitlyn Gaynor, “and we are driving all the other mammals back into the night-time.” The Southeast Asian sun bear, formerly diurnal, now spends as much as 70 percent more time awake at night to avoid humans.

A longtime practice of European peasants was to bring cows and sheep inside for the night. If one could ignore “the nastiness of their excrements,” a late seventeenth-century visitor to Ireland opined, “the sweetness of their breath” and “the pleasing noise they made in ruminating or chewing the cud” might lull a person to sleep. A visitor to the Hebrides noted, however, that while urine was regularly collected and discarded, the dung was removed only once a year.

When a boat of carousing European sailors on the Bosporus awoke the sleeping Sultan Selim III one night in 1790, the Ottoman leader issued an emergency order to his administration against night revelers: “Warn all ambassadors and Europeans never to perform this shameless act again. I will mercilessly kill whoever does it.”

The practice of yobai, “night crawling,” was common in rural communities in medieval Japan, and continued into the twentieth century. A young man would visit a young woman’s house after dark, disguising his features with a cloth to avoid embarrassment should his advances be rejected. These premarital liaisons could become formal if a child were conceived.

Emily and Charlotte Brontë, insomniacs both, would walk together in circles around the dining room table until they were tired enough to sleep. When Emily died and Charlotte suffered alone, her insomnia worsened; she added to her route, often wandering down neighborhood streets and into the cemetery until daybreak.