His student, Aserinsky, who discovered the phenomenon of rapid eye movement, or REM, did so by looking, for want of something better to do, at eyelid movement in sleeping subjects. Aserinsky’s assistant, Dement, intended to be a psychiatrist but realized, while in one of Kleitman’s lectures, that in order to know about the waking brain, one needed to study sleep. As he put it, “During that lecture it occurred to me that the way to understand consciousness is to understand what must be given up to enter unconsciousness.”
Then there’s Carskadon, who drove policy changes around school start times to better suit the sleep needs of teenagers. The only prominent woman in a history that is depressingly, overwhelmingly male, Carskadon was left-field: a cousin of Dement’s wife who ambled, with no formal qualifications, into a long and fruitful career in sleep research.
Miller is superb at identifying and then interweaving the multiple confluences of this sprawling subject. There are interesting discussions of sleep disorders and of the impact of impaired sleep on society. But the most fascinating of the book’s threads is that of REM sleep — le sommeil paradoxal, as it has been called. First there was the link, discovered by Aserinsky, Dement and Kleitman, between REM and dreams, and then the subsequent decades of research into what this state is, where in the brain it happens, when it happens and its purpose.
I found myself studding the margins with exclamation marks, as Miller carries the reader through these dark mysteries, leading us to points of light that serve only to illuminate more mystery. We learn that REM sleep is what the French researcher Michel Jouvet called a “third state of the brain, as different from sleep as sleep is from wakefulness.” If deprived of it, we experience a “REM rebound” as soon as we sleep again — we plunge more quickly into the REM phase and stay there longer, to compensate. In Miller’s hands, sleep is a territory of seductive, wondrous mystery, and his great achievement is balancing rigor and awe.
“One of the paradoxes of sleep science (and, perhaps, most other sciences),” Miller writes, “is that it often violates the precepts of Occam’s razor — the principle that between two competing theories, the simpler explanation is to be preferred.” We’ve long known that there is nothing simple about sleep; Miller introduces us to its farthest reaches. Our growing understanding of this stubborn, beautiful enigma will inform our waking consciousness, too.
