Nowadays, it’s common to see advertisements for all manner of sleep-related products, from sleep trackers to CPAP machines to sunrise alarm clocks. Similarly, it’s not unusual for people to enthusiastically discuss sleep hygiene, circadian rhythms or owl vs. lark tendencies. Self-awareness is a beautiful thing, but how did we get here? After all, as Discover magazine contributor Kenneth Miller reveals in his engrossing Mapping the Darkness: The Visionary Scientists Who Unlocked the Mysteries of Sleep, “Just a century ago, only a handful of scientists studied sleep. . . . Most saw slumber as a nonevent,” something that “could be safely minimized or eliminated altogether.”
But there were outliers, Miller explains, academics who knew sleep was not merely a pause but rather the precious foundation of our waking hours. In Mapping the Darkness, the author has crafted linked biographies of four groundbreaking scientists—Nathan Kleitman, who in the 1920s incited a cascade of scholarly interest in sleep; Eugene Aserinksy, a student of Kleitman’s; William Dement, Kleitman’s mentee; and Mary Carskadon, who started as Dement’s lab assistant—and the ways in which their discoveries resulted in our present-day understanding of sleep.
In 1938, Kleitman and colleagues lived in a Kentucky cave for a month to examine sleep cycles. Over 20 years later, in the 1960s, Dement set up a cat-filled lab in a Quonset hut near Stanford University to focus on REM sleep. The fruits of these experiments and the research they subsequently inspired were helpful in analyzing root causes of the 1986 Challenger space shuttle tragedy (sleep deprivation was a contributing factor) and understanding teenagers’ need for more sleep than their younger counterparts.
Among many other topics, Miller also chronicles research into the impact of shift work on sleep, treatments for sleep apnea and important sleep-related studies Carskadon is conducting today. But while knowledge is certainly power, he cautions that we’re still experiencing “society’s ongoing, and ever-escalating, assault on sleep” due to digital devices, poor work habits and more. The impressive work of reportage that is Mapping the Darkness is an impassioned reminder to appreciate the researchers whose work has transformed our slumber—and do our best to give sleep the respect and attention it deserves.