The definitive story of the scientists who set out to answer two questions: “Why do we sleep?” and "How can we sleep better?”

A century ago, sleep was considered a state of nothingness—even a primitive habit that we could learn to overcome. Then, an immigrant scientist and his assistant spent a month in the depths of a Kentucky cave, making nationwide headlines and thrusting sleep science to the forefront of our consciousness.

In the 1920s, Nathaniel Kleitman founded the world’s first dedicated sleep lab at the University of Chicago, where he subjected research participants (including himself) to a dizzying array of tests and tortures. But the tipping point came in 1938, when his cave experiment awakened the general public to the unknown—and vital—world of sleep. Kleitman went on to mentor the talented but troubled Eugene Aserinsky, whose discovery of REM sleep revealed the astonishing activity of the dreaming brain, and William Dement, a jazz-bass playing revolutionary who became known as the father of sleep medicine. Dement, in turn, mentored the brilliant maverick Mary Carskadon, who uncovered an epidemic of sleep deprivation among teenagers, and launched a global movement to fight it.

Award-winning journalist Kenneth Miller weaves together science and history to tell the story of four outsider scientists who took sleep science from fringe discipline to mainstream obsession through spectacular experiments, technological innovation, and single-minded commitment. Readers will walk away with a comprehensive understanding of sleep and why it affects so much of our lives.